These release notes describe changes that have been made since the previous release of this series of EPICS Base. Note that changes which were merged up from commits to new releases in an older Base series are not described at the top of this file but have entries that appear lower down, under the series to which they were originally committed. Thus it is important to read more than just the first section to understand everything that has changed in each release.

The external PVA submodules each have their own separate set of release notes which should also be read to understand what has changed since an earlier release.

EPICS Release

Build System changes

EPICS_BASE_VERSION Update Policy change

In the past, a build of EPICS using sources checked out from the repository branch between official releases would have shown the version number of the previous release, followed by a -DEV suffix, for example

The policy that controls when the number gets updated has been changed, and now immediately after a release has been tagged the version number will be updated to the next patch release version, plus the -DEV suffix as before. Thus following the version number will show as This does not require the next official release to be numbered though, it could become 7.0.3 or even 7.1.0 if the changes incorporated into it are more substantial than bug fixes.

Drop CLOCK_MONOTONIC_RAW from posix/osdMonotonic.c

Turns out this is ~10x slower to query than CLOCK_MONOTONIC.

EPICS Release

Linking shared libraries on macOS

The linker flag -flat_namespace has been restored for creating shared libraries, although not for loadable libraries (bundles). This was required for building using the latest versions of Apple XCode.

Fix DB_LINK loop breaking

A regression was introduced in 7.0.2 which caused record chains with loops to be incorrectly broken. Processing should be skipped when a DB_LINK with Process Passive (PP) closes a loop to a synchronous record.

Instead in 7.0.2 the targeted record would be processed if processing began with a remote action (or some other caller of dbPutField()). This would result in the loop running a second time. The loop would be broken on the second iteration.

See lp: #1809570

Old dbStaticLib APIs removed

Support for some obsolete dbStaticLib Database Configuration Tool (DCT) APIs was removed some time ago, but vestiges of them still remained. The following routines and macros and have now finally been removed:

Fix for dbhcr before iocInit

The dbhcr command used to work before iocInit as well as afterwards. It displays all records that have hardware addresses (VME_IO, CAMAC_IO, GPIB_IO, INST_IO etc.) but stopped working if run before iocInit due to the rewrite of the link address parser code in dbStaticLib. This release fixes that issue, although in some cases the output may be slightly different than it used to be.

EPICS Release 7.0.2

Launchpad Bugs

The list of tracked bugs fixed in this release can be found on the Launchpad Milestone page for EPICS Base 7.0.2.

Git Branches Recombined

The four separate Git branches core/master, libcom/master, ca/master and database/master have been recombined into one branch called 7.0. Keeping these as 4 separate branches in the same repository made it impossible to create merge requests that contained changes in more than one of these modules. The layout of the source files has not changed at all however, so the source code for libcom, ca and the database are still found separately under the module subdirectory.

EPICS Release

Changed SIML failure behavior

A failure when fetching the simulation mode through SIML will not put the record into INVALID alarm state anymore. Instead, as long as the record's current alarm severity (SEVR)is NO_ALARM, its alarm status (STAT) will be set to LINK_ALARM without increasing the severity. This allows clients to get some notification of a failing or bad SIML link without otherwise affecting record processing.

dbVerify() has been restored to dbStaticLib

This routine was removed in Base-3.16.1 but has been reimplemented in this release by special request. Note that the error message strings that it returns when verification fails have changed, but are still designed for display to the user.

Simulation mode improvements

Records that support simulation mode have two new fields, SSCN (Simulation Scan Mode) and SDLY (Simulation Delay). SSCN is a menu field that provides an alternate value for the SCAN field to be used while the record is in simulation mode. This is especially useful for I/O scanned records, for which simulation mode was not working at all. Setting SDLY to a positive value makes the record process asynchronously in simulation mode, with the second stage processing happening after the specified time (in seconds).

Extend the dbServer API with init/run/pause/stop methods

This change permits IOCs to be built that omit the CA server (RSRV) by removing its registrar entry which is now provided in the new rsrv.dbd file. Other server layers can be built into the IOC (alongside RSRV or in place of it) by registering them in a similar manner. The dbServer API is documented with Doxygen comments in the header file.

Specific IOC server layers can be disabled at runtime by adding their name to the environment variable EPICS_IOC_IGNORE_SERVERS (separated by spaces if more than one should be ignored).

Grand source-code reorganization

EPICS 7.0.1 contains the IOC Database, RSRV server and the Channel Access client code from EPICS Base 3.16.1 along with all the original record types and soft device support, but GDD and the Portable Channel Access Server have been unbundled and are now available separately. In their place we have brought in the more recently written EPICS V4 C++ libraries (collectively referred to as the PVA modules). The directory tree for EPICS is somewhat larger as a result, and the original structure of the Base directories has been split into 4 separate Git repositories. External modules should build against this new structure with little or no changes needed, except that some allowance may be needed for the merging of the V4 modules.

There should be rather more description and documantation of these changes than is currently available, but as developers we generally much prefer to write code than documentation. Send questions to the tech-talk mailing list and we'll be happy to try and answer them!

Changes between 3.16.1 and 3.16.2

The list of tracked bugs fixed in this release can be found on the Launchpad Milestone page for EPICS Base 3.16.2.

Status reporting for the callback and scanOnce task queues

Two new iocsh commands and some associated underlying APIs have been added to show the state of the queues that feed the three callback tasks and the scanOnce task, including a high-water mark which can optionally be reset. The new iocsh commands are callbackQueueShow and scanOnceQueueShow; both take an optional integer argument which must be non-zero to reset the high-water mark.

Support for event codes greater than or equal to NUM_TIME_EVENTS

Event numbers greater than or equal to NUM_TIME_EVENTS are now allowed if supported by the registered event time provider, which must provide its own advancing timestamp validation for such events.

Time events numbered 0 through (NUM_TIME_EVENTS-1) are still validated by code in epicsGeneralTime.c that checks for advancing timestamps and enforces that restriction.

Type-safe Device and Driver Support Tables

Type-safe versions of the device and driver support structures dset and drvet have been added to the devSup.h and drvSup.h headers respectively. The original structure definitions have not been changed so existing support modules will still build normally, but older modules can be modified and new code written to be compatible with both.

The old structure definitions will be replaced by the new ones if the macros USE_TYPED_DSET and/or USE_TYPED_DRVET are defined when the appropriate header is included. The best place to define these is in the Makefile, as with the USE_TYPED_RSET macro that was introduced in Base-3.16.1 and described below. See the comments in devSup.h for a brief usage example, or look at this commit to the ipac module to see a module conversion.

A helper function DBLINK* dbGetDevLink(dbCommon *prec) has also been added to devSup.h which fetches a pointer to the INP or OUT field of the record.

RTEMS build configuration update, running tests under QEMU

This release includes the ability to run the EPICS unit tests built for a special version of the RTEMS-pc386 target architecture on systems that have an appropriate QEMU emulator installed (qemu-system-i386). It is also now possible to create sub-architectures of RTEMS targets, whereas previously the EPICS target architecture name had to be RTEMS-$(RTEMS_BSP).

The new target RTEMS-pc386-qemu builds binaries that can be run in the qemu-system-i386 PC System emulator. This target is a derivative of the original RTEMS-pc386 target but with additional software to build an in-memory file-system, and some minor modifications to allow the unit tests to work properly under QEMU. When this target is enabled, building any of the make targets that cause the built-in self-tests to be run (such as make runtests) will also run the tests for RTEMS using QEMU.

To allow the new 3-component RTEMS target name, the EPICS build system for RTEMS was modified to allow a configure/os/CONFIG.Common.<arch> file to set the RTEMS_BSP variable to inform the build what RTEMS BSP to use. Previously this was inferred from the value of the T_A make variable, but that prevents having multiple EPICS targets that build against the same BSP. All the included RTEMS target configuration files have been updated; build configuration files for out-of-tree RTEMS targets will continue to work as the original rules are used to set RTEMS_BSP if it hasn't been set when needed.

Link type enhancements

This release adds three new link types: "state", "debug" and "trace". The "state" link type gets and puts boolean values from/to the dbState library that was added in the 3.15.1 release. The "debug" link type sets the jlink::debug flag in its child link, while the "trace" link type also causes the arguments and return values for all calls to the child link's jlif and lset routines to be printed on stdout. The debug flag can no longer be set using an info tag. The addition of the "trace" link type has allowed over 200 lines of conditional diagnostic printf() calls to be removed from the other link types.

The "calc" link type can now be used for output links as well as input links. This allows modification of the output value and even combining it with values from other input links. See the separate JSON Link types document for details.

A new start_child() method was added to the end of the jlif interface table.

The lset methods have now been properly documented in the dbLink.h header file using Doxygen annotations, although we do not run Doxygen on the source tree yet to generate API documentation.

Link types that utilize child links must now indicate whether the child will be used for input, output or forward linking by the return value from its parse_start_map() method. The jlif_key_result enum now contains 3 values jlif_key_child_inlink, jlif_key_child_outlink and jlif_key_child_fwdlink instead of the single jlif_key_child_link that was previously used for this.

GNUmake targets for debugging

Some additional build rules have been added to help debug configuration problems with the build system. Run make show-makefiles to get a sorted list of all the files that the build system includes when building in the current directory.

A new pattern rule for PRINT.% can be used to show the value of any GNUmake variable for the current build directory (make sure you are in the right directory though, many variables are only set when inside the O.arch build directory). For example make PRINT.T_A will display the build target architecture name from inside a O.arch directory but the variable will be empty from an application top or src directory. make PRINT.EPICS_BASE will show the path to Base from any EPICS application directory though.

Propagate PUTF across Asynchronous record processing

The IOC contains a mechanism involving the PUTF and RPRO fields of each record to ensure that if a record is busy when it receives a put to one of its fields, the record will be processed again to ensure that the new field value has been correctly acted on. Until now that mechanism only worked if the put was to the asynchronous record itself, so puts that were chained from some other record via a DB link did not cause reprocessing.

In this release the mechanism has been extended to propagate the PUTF state across DB links until all downstream records have been reprocessed. Some additional information about the record state can be shown by setting the TPRO field of an upstream record, and even more trace data is displayed if the debugging variable dbAccessDebugPUTF is set in addition to TPRO.

Finding info fields

A new iocsh command dbli lists the info fields defined in the database, and can take a glob pattern to limit output to specific info names. The newly added dbStaticLib function dbNextMatchingInfo() iterates through the info fields defined in the current record, and is used to implement the new command.

Output from dbpr command enhanced

The "DataBase Print Record" command dbpr now generates slightly better output, with more field types having their own display methods. This release also includes additional protection against buffer overflows while printing long links in dbpr, and corrects the output of long strings from the dbgf command.

Record types mbbiDirect and mbboDirect upgraded to 32 bit

The VAL fields and related fields of these records are now DBF_LONG. (Not DBF_ULONG in order to prevent Channel Access from promoting them to DBF_DOUBLE.) Additional bit fields B10...B1F have been added.

Device support that accesses VAL or the bit fields directly (most don't) and aims for compatibility with old and new versions of these records should use at least 32 bit integer types to avoid bit loss. The number of bit fields can be calculated using 8 * sizeof(prec->val) which is correct in both versions.

Restore use of ledlib for VxWorks command editing

The epicsReadline refactoring work described below unfortunately disabled the VxWorks implementation of the osdReadline.c API that uses ledlib for command editing and history. This functionality has now been restored, see Launchpad bug #1741578.

Constant link types

Constant links can now hold 64-bit integer values, either as scalars or arrays. Only base 10 is supported by the JSON parser though, the JSON standard doesn't allow for hexadecimal numbers.

Upgraded the YAJL JSON Library

The third-party YAJL library that has been included in libCom for several years has been upgraded to version 2.1.0 and several bugs fixed. This has an updated API, requiring any code that uses it to parse its own JSON files to be modified to match. The changes are mainly that it uses size_t instead unsigned int for string lengths, but it also uses long long instead of long for JSON integer values, which was the main motivation for the upgrade.

The self-tests that YAJL comes with have been imported and are now run as an EPICS Unit Test program, and the JSON syntax accepted by the parser was extended to permit trailing commas in both arrays and maps. The difference between the old and new YAJL APIs can be detected at compile time by looking for the macro EPICS_YAJL_VERSION which is defined in the yajl_common.h header file along with a brief description of the API changes.

Timestamp support for the calc link type

A new optional parameter can be given when specifying a calc JSON link. The time parameter is a string containing a single letter A..L that selects one of the input links to be used for the timestamp of calculation if requested. The timestamp will be fetched atomically with the value from the chosen input link (providing that input link type supports the readLocked() method).

Silence errors from puts to constant link types

A soft channel output record with the OUT link unset uses the CONSTANT link type. The new link type code was causing some soft channel device supports to return an error status from the write method of that link type, which would cause a ca_put() operation to such a record to generate an exception. This has been silenced by giving the constant link types a dummy putValue method. A new test program has been added to prevent regressions of this behaviour.

RSRV expanding large buffer causes crash

In the 3.16.1 release a crash can occur in the IOC's RSRV server when a large array is made even larger; the previous array buffer was not being released correctly. See Launchpad bug #1706703.

Changes made between and 3.16.1

IOC Database Support for 64-bit integers

The IOC now supports the 64-bit integer field types DBF_INT64 and DBF_UINT64, and there are new record types int64in and int64out derived from the longin and longout types respectively that use the DBF_INT64 data type for their VAL and related fields. The usual range of Soft Channel device support are included for these new record types.

All internal IOC APIs such as dbAccess can handle the new field types and their associated request values DBR_INT64 and DBR_UINT64, which are implemented using the epicsInt64 and epicsUInt64 typedef's from the epicsTypes.h header.

The waveform record type has been updated to support these new field types. All waveform device support layers must be updated to recognize the new type enumeration values, which had to be inserted before the FLOAT value in the enum dbfType and in menuFtype. C or C++ code can detect at compile-time whether this version of base provides 64-bit support by checking for the presence of the DBR_INT64 macro as follows (Note that DBF_INT64 is an enum tag and not a preprocessor macro):

#ifdef DBR_INT64
    /* Code where Base has INT64 support */
    /* Code for older versions */

If the code uses the old db_access.h types (probably because it's calling Channel Access APIs) then it will have to test against the EPICS version number instead, like this:

#include <epicsVersion.h>

#  define VERSION_INT(V,R,M,P) ( ((V)<<24) | ((R)<<16) | ((M)<<8) | (P))

    /* Code where Base has INT64 support */
    /* Code for older versions */

Channel Access does not (and probably never will) directly support 64-bit integer types, so the new field types are presented to the CA server as DBF_DOUBLE values. This means that field values larger than 2^52 (0x10_0000_0000_0000 = 4503599627370496) cannot be transported over Channel Access without their least significant bits being truncated. The EPICS V4 pvAccess network protocol can transport 64-bit data types however, and a future release of the pvaSrv module will connect this ability to the fields of the IOC.

Additional 64-bit support will be provided in later release. For instance the JSON parser for the new Link Support feature only handles integers up to 32 bits wide, so constant array initializer values cannot hold larger values in this release.


A new environment parameter EPICS_CA_MCAST_TTL is used to set the Time To Live (TTL) value of any IP multi-cast CA search or beacon packets sent.


A new environment parameter EPICS_CA_AUTO_ARRAY_BYTES is now used by libca and RSRV (CA clients and the IOC CA server). The default is equivalent to setting EPICS_CA_AUTO_ARRAY_BYTES=YES which removes the need to set EPICS_CA_MAX_ARRAY_BYTES and always attempts to allocate sufficiently large network buffers to transfer large arrays properly over the network. In this case the value of the EPICS_CA_MAX_ARRAY_BYTES parameter is ignored.

Explicitly setting EPICS_CA_AUTO_ARRAY_BYTES=NO will continue to honor the buffer setting in EPICS_CA_AUTO_ARRAY_BYTES as in previous releases.

The default setting for EPICS_CA_AUTO_ARRAY_BYTES can be changed by adding the line


to the configure/CONFIG_SITE_ENV file before building Base. Sites that wish to override this only for specific IOC architectures can create new files for each architecture named configure/os/CONFIG_SITE_ENV.<target-arch> with the above setting in before building Base. The configuration can also be explicitly changed by setting the environment variable in the IOC's startup script, anywhere above the iocInit line.

The PCAS server (used by the PV Gateway and other CA servers) now always behaves as if EPICS_CA_AUTO_ARRAY_BYTES is set to YES (it ignores the configuration parameter and environment variable).

Channel Access "modernization"

Drop support for CA clients advertising protocol versions less than 4.

This effects clients from Base older than 3.12.0-beta1. Newer clients will continue to be able to connect to older servers. Older clients will be ignored by newer servers.

This allows removal of UDP echo and similar protocol features which are not compatible with secure protocol design practice.

Lookup-tables using the subArrray record

The subArray record can now be used as a lookup-table from a constant array specified in its INP field. For example:

record(subArray, "powers-of-2") {
  field(FTVL, "LONG")
  field(MALM, 12)
  field(INP, [1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048])
  field(INDX, 0)
  field(NELM, 1)

The INDX field selects which power of 2 to set the VAL field to. In previous releases the INP field would have to have been pointed to a separate waveform record that was initialized with the array values somehow at initialization time.

Synchronized Timestamps with TSEL=-2

Most Soft Channel input device support routines have supported fetching the timestamp through the INP link along with the input data. However before now there was no guarantee that the timestamp provided by a CA link came from the same update as the data, since the two were read from the CA input buffer at separate times without maintaining a lock on that buffer in between. This shortcoming could be fixed as a result of the new link support code, which allows code using a link to pass a subroutine to the link type which will be run with the link locked. The subroutine may make multiple requests for metadata from the link, but must not block.

Extensible Link Types

A major new feature introduced with this release of EPICS Base is an Extensible Link Type mechanism, also known as Link Support or JSON Link Types. This addition permits new kinds of link I/O to be added to an IOC in a similar manner to the other extension points already supported (e.g. record, device and driver support).

A new link type must implement two related APIs, one for parsing the JSON string which provides the link address and the other which implements the link operations that get called at run-time to perform I/O. The link type is built into the IOC by providing a new link entry in a DBD file.

New Link Types Added

This release contains two new JSON link types, const and calc:

  field(INP, {calc:{expr:"A+B+1",
                    args:[5,         # A
                          {const:6}] # B

The new link types are documented in a separate document .

Device Support Addressing using JSON_LINK

The API to allow device support to use JSON addresses is currently incomplete; developers are advised not to try creating device support that specifies a JSON_LINK address type.

Support Routine Modifications for Extensible Link Types

For link fields in external record types and soft device support to be able to use the new link types properly, various changes are required to utilize the new Link Support API as defined in the dbLink.h header file and outlined below. The existing built-in Database and Channel Access link types have been altered to implement the link APIs, so will work properly after these conversions:

Constant Link Values

Previously a constant link (i.e. a link that did not point to another PV, either locally or over Channel Access) was only able to provide a single numeric value to a record initialization; any string given in a link field that was not recognized as a number was treated as a PV name. In this release, constant links can be expressed using JSON array syntax and may provide array initialization of values containing integers, doubles or strings. An array containing a single string value can also be used to initialize scalar strings, so the stringin, stringout, lsi (long string input), lso (long string output), printf, waveform, subArray and aai (analog array input) record types and/or their soft device supports have been modified to support this.

Some examples of constant array and string initialized records are:

  record(stringin, "const:string") {
    field(INP, ["Not-a-PV-name"])
  record(waveform, "const:longs") {
    field(FTVL, LONG)
    field(NELM, 10)
    field(INP, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
  record(aai, "const:doubles") {
    field(FTVL, DOUBLE)
    field(NELM, 10)
    field(INP, [0, 1, 1.6e-19, 2.718, 3.141593])
  record(aSub, "select") {
    field(FTA, STRING)
    field(NOA, 4)
    field(INPA, ["Zero", "One", "Two", "Three"])
    field(FTB, SHORT)
    field(NOB, 1)
    field(FTVA, STRING)
    field(NOVA, 1)
    field(SNAM, "select_asub")

Reminder: Link initialization with constant values normally only occurs at record initialization time. The calcout and printf record types are the only exceptions in the Base record types to this rule, so it is generally not useful to change a const link value after iocInit.

Database Parsing of "Relaxed JSON" Values

A database file can now provide a "relaxed JSON" value for a database field value or an info tag. Only a few field types can currently accept such values, but the capability is now available for use in other places in the future. When writing to a JSON-capable field at run-time however, only strictly compliant JSON may be used (the dbStaticLib parser rewrites relaxed JSON values into strict JSON before passing them to the datase for interpretation, where the strict rules must be followed).

"Relaxed JSON" was developed to maximize compatibility with the previous database parser rules and reduce the number of double-quotes that would be needed for strict JSON syntax. The parser does accept strict JSON too though, which should be used when machine-generating database files. The differences are:

A JSON field or info value is only enclosed in quotes when the value being provided is a single string, and even here the quotes can be omitted in some cases as described above. The following shows both correct and incorrect excerpts from a database file:

    record(ai, math:pi) {
        field(INP, {const: 3.14159265358979})   # Correct
        field(SIOL, "{const: 3.142857}")        # Wrong

        info(autosave, {            # White-space and comments are allowed
            fields:[DESC, SIMM],
        })                          # Correct

Note that the record, field and info-tag names do not accept JSON values, so they follows the older bareword rules for quoting where the colon : and several additional characters are legal in a bareword string. Only the value (after the comma) is parsed as JSON. The autosave module has not been modified to accept JSON syntax, the above is only an example of how JSON might be used.

Echoless comments in iocsh

The way comments are parsed by the iocsh interpreter has changed. The interpreter can be selectively disabled from echoing comments coming from a script by starting those lines with '#-' rather than just '#'.

Typed record support methods

The table of record support functions (rset methods for short) no longer has entries of type RECSUPFUN (which says: any number and type of arguments). Instead, rset methods are now typed by default. The RECSUPFUN typedef has been deprecated and casts to it as well as using the untyped struct rset will create compilation warnings.

Existing code (e.g. external record supports) will generate such warnings when compiled against this version of Base, but it will work without changes.

For a conversion period, the new typed rset definitions are activated by defining USE_TYPED_RSET, preferably by setting USR_CPPFLAGS += -DUSE_TYPED_RSET inside a Makefile. After activating the new typed rset in this way and making the following changes, the result should still compile and work properly against older versions of Base.

The first parameter of init_record and process has been changed to struct dbCommon *. Record types that use void* here should be changed to use struct dbCommon*, and cast the argument to their own xxxRecord *.

When compiled against this release, compiler warnings about incompatible types for the method pointers should be taken seriously. When compiled against older versions of base, such warnings are unavoidable.

Record types written in C++ need to take more drastic measures because of the stricter type checking in C++. To remain compatible with older versions of base you will need to use something like:

#include "epicsVersion.h"
#  else
#    define RECSUPFUN_CAST
#  endif

and then replace (RECSUPFUN) with RECSUPFUN_CAST when initializing the rset. Further changes might also be needed, e.g. to adapt const-ness of method parameters.

Changes made between 3.15.3 and

Build support for CapFast and dbst removed

The build rules associated with the CapFast-related tools sch2edif and e2db and the database optimization tool dbst have been removed, along with the DB_OPT build configuration variable.

compressRecord buffering order

The compressRecord has a new field BALG which can select between FIFO (append) and LIFO (prepend) ordering for insertion of new elements. FIFO ordering is the default, matching the behviour of previous versions.

Valgrind Instrumentation

Valgrind is a software debugging suite provided by many Linux distributions. The header valgrind/valgrind.h is now included in, and installed by, Base. When included by a C or C++ source file this header defines some macros which expand to provide hints to the Valgrind runtime. These have no effect on normal operation of the software, but when run using the valgrind tool they can help to find memory leaks and buffer overflows. Suitable hints have been added to several free-lists within libCom, including freeListLib, allowing valgrind to provide more accurate information about the source of potential leaks.

valgrind.h automatically disables itself when the build target is not supported by the valgrind tool. It can also explicitly be disabled by defining the macro NVALGRIND. See src/libCom/Makefile for a commented-out example.

As a matter of policy valgrind.h will never be included by any header file installed by Base, so its use will remain purely an implementation detail hidden from application software. Support modules which choose to use valgrind.h are advised to do likewise.

Database Multi-locking

The IOC record locking code has been re-written with an expanded API; global locks are no longer required by the IOC database implementation.

The new API functions center around dbScanLockMany(), which behaves like dbScanLock() applied to an arbitrary group of records. dbLockerAlloc() is used to prepare a list or record pointers, then dbScanLockMany() is called. When it returns, all of the records listed may be accessed (in any order) until dbScanUnlockMany() is called.

The Application Developer's Guide has been updated to describe the API and implementation is more detail.

Previously a global mutex 'lockSetModifyLock' was locked and unlocked during dbScanLock(), acting as a sequencing point for otherwise unrelated calls. The new dbLock.c implementation does not include any global mutex in dbScanLock() or dbScanLockMany(). Locking/unlocking of unrelated lock sets is now completely concurrent.

Generate Version Header

A Perl script and Makefile rules have been added to allow modules to generate a C header file with a macro defined with an automatically updated identifier. This is a VCS revision ID (Darcs, Git, Mercurial, Subversion, and Bazaar are supported) or the date/time of the build if no VCS system is in use.

The makeBaseApp example template has been updated with a new device support which makes this identifier visible via a lsi (long string input) record.

epicsTime API return status

The epicsTime routines that used to return epicsTimeERROR now return a specific S_time_ status value, allowing the caller to discover the reason for any failure. The identifier epicsTimeERROR is no longer defined, so any references to it in source code will no longer compile. The identifier epicsTimeOK still exists and has the value 0 as before, so most code that uses these APIs can be changed in a way that is backwards-compatible with the previous return status.

Time providers that have to return a status value and still need to be built with earlier versions of Base can define the necessary status symbols like this:

#include "epicsTime.h"

#ifndef M_time
/* S_time_... status values were not provided before Base 3.16 */
#define S_time_unsynchronized epicsTimeERROR
#define S_time_...whatever... epicsTimeERROR

Refactoring of epicsReadline

The epicsReadline code has been reorganized to allow the commandline history editor to be disabled at runtime. The EPICS_COMMANDLINE_LIBRARY build setting still selects the preferred editor, but the new IOCSH_HISTEDIT_DISABLE environment variable can be set at runtime to disable history editing and make the IOC or other program use the basic editor instead. This is useful when starting and controlling an IOC from another program through its stdin and stdout streams since history editors often insert invisible escape codes into the stdout stream, making it hard to parse.

Callback subsystem API

Added a new macro callbackGetPriority(prio, callback) to the callback.h header and removed the need for dbScan.c to reach into the internals of its CALLBACK objects.

Changes from the 3.15 branch since 3.15.6

Perl CA bindings fixed for macOS Mojave

Apple removed some Perl header files from macOS Mojave that were available in their SDK, requiring a change to the include paths used when compiling the CA bindings. The new version should build on new and older macOS versions, and these changes may also help other targets that have an incomplete installation of Perl (the build will continue after printing a warning that the Perl CA bindings could not be built).

Routine epicsTempName() removed from libCom

This routine was a simple wrapper around the C89 function tmpnam() which is now seen as unsafe and causes warning messages to be generated by most modern compilers. The two internal uses of this function have been modified to call epicsTempFile() instead. We were unable to find any published code that used this function, so it was removed immediately instead of being deprecated.

DBD Parsing of Record Types

The Perl DBD file parser has been made slightly more liberal; the order in which DBD files must be parsed is now more flexible, so that a record type definition can now be parsed after a device support that referred to that record type. A warning message will be displayed when the device support is seen, but the subsequent loading of the record type will be accepted without triggering an error. See Launchpad bug #1801145.

menuScan and several record types documented with POD

The EPICS Wiki pages describing a number of standard record types has been converted into the Perl POD documentation format and added to the DBD files, so at build-time an HTML version of these documents is generated and installed into the htmls directory. Thanks to Tony Pietryla.

CA client tools learned -V option

This displays the version numbers of EPICS Base and the CA protocol.

Changes made between 3.15.5 and 3.15.6

Unsetting environment variables

The new command epicsEnvUnset varname can be used to unset an environment variable.

Warning indicators in msi (and macLib) output

The libCom macro expansion library has been modified so that when the SUPPRESS_WARNINGS flag is set it will no longer include any ,undefined or ,recursive indicators in its output when undefined or recursive macros are encountered. These indicators were harmless when the output was fed into an IOC along with a definition for the macro, but when the msi tool was used to generate other kinds of files they caused problems. If the msi -V flag is used the markers will still be present in the output whenever the appropriate condition is seen.

Improvements to msi

In addition to fixing its response to discovering parsing errors in its substitution input file (reported as Launchpad bug #1503661) so it now deletes the incomplete output file, the msi program has been cleaned up a little bit internally.

All array records now post monitors on their array-length fields

The waveform record has been posting monitors on its NORD field since Base; we finally got around to doing the equivalent in all the other built-in record types, which even required modifying device support in some cases. This fixes Launchpad bug #1730727.

HOWTO: Converting Wiki Record Reference to POD

Some documentation has been added to the script explaining how Perl POD (Plain Old Documentation) markup can be added to .dbd files to generate HTML documentation for the record types. To see these instructions, run perl bin/<host>/ -H or perldoc bin/<host>/

Fix problem with numeric soft events

Changing from numeric to named soft events introduced an incompatibility when a numeric event 1-255 is converted from a DOUBLE, e.g. from a calc record. The post_event() API is not marked deprecated any more.

Also scanpel has been modified to accept a glob pattern for event name filtering and to show events with no connected records as well.

Add osiSockOptMcastLoop_t and osiSockTest

Added a new OS-independent typedef for multicast socket options, and a test file to check their correct operation.

Support for CONFIG_SITE.local in Base

This feature is mostly meant for use by developers; configuration settings that would normally appear in Base/configure/CONFIG_SITE can now be put in a locally created base/configure/CONFIG_SITE.local file instead of having go modify or replace the original. A new .gitignore pattern tells git to ignore all configure/*.local files.

Changes from the 3.14 branch between 3.15.5 and 3.15.6

Fix broken EPICS_IOC_LOG_FILE_LIMIT=0 setting

The Application Developers' Guide says this is allowed and disables the limit on the log-file, but it hasn't actually worked for some time (if ever). Note that the iocLogServer will be removed from newer Base release sometime soon as its functionality can be implemented by other dedicated log servers such as logstash or syslog-ng.

Fixes lp:1786858 and part of lp:1786966.

Cleanup of startup directory

The files in the startup directory have not been maintained in recent years and have grown crufty (technical term). This release includes the following updates to these files:

Recent Apple XCode Build Issues

The latest version of XCode will not compile calls to system() or clock_settime() for iOS targets. There were several places in Base where these were being compiled, although there were probably never called. The code has now been modified to permit iOS builds to complete again.

Prevent illegal alarm severities

A check has been added to recGblResetAlarms() that prevents records from getting an alarm severity higher than INVALID_ALARM. It is still possible for a field like HSV to get set to a value that is not a legal alarm severity, but the core IOC code should never copy such a value into a record's SEVR or ACKS fields. With this fix the record's alarm severity will be limited to INVALID_ALARM.

Fixes for Launchpad bugs

The following launchpad bugs have fixes included:

Updated VxWorks Timezone settings

Removed the settings for 2017; fixed the hour of the change for MET.

Fixed camonitor server side relative timestamps bug

Initialize the first time-stamp from the first monitor, not the client-side current time in this configuration.

Build changes for MSVC

Windows builds using Visual Studio 2015 and later now use the -FS compiler option to allow parallel builds to work properly.

We now give the -FC option to tell the compiler to print absolute paths for source files in diagnostic messages.

Extend maximum Posix epicsEventWaitWithTimeout() delay

The Posix implementation of epicsEventWaitWithTimeout() was limiting the timeout delay to at most 60 minutes (3600.0 seconds). This has been changed to 10 years; significantly longer maximum delays cause problems on systems where time_t is still a signed 32-bit integer so cannot represent absolute time-stamps after 2038-01-19. Our assumption is that such 32-bit systems will have been retired before the year 2028, but some additional tests have been added to the epicsTimeTest program to detect and fail if this assumption is violated.

New test-related make targets

This release adds several new make targets intended for use by developers and Continuous Integration systems which simplify the task of running the built-in self-test programs and viewing the results. Since these targets are intended for limited use they can have requirements for the build host which go beyond the standard minimum set needed to build and run Base.

test-results — Summarize test results

The new make target test-results will run the self-tests if necessary to generate a TAP file for each test, then summarizes the TAP output files in each test directory in turn, displaying the details of any failures. This step uses the program prove which comes with Perl, but also needs cat to be provided in the default search path so will not work on most Windows systems.

junitfiles — Convert test results to JUnit XML Format

The new make target junitfiles will run the self-tests if necessary and then convert the TAP output files into the more commonly-supported JUnit XML format. The program that performs this conversion needs the Perl module XML::Generator to have been installed.

clean-tests — Delete test result files

The new make target clean-tests removes any test result files from previous test runs. It cleans both TAP and JUnit XML files.

Fix DNS related crash on exit

The attempt to fix DNS related delays for short lived CLI programs (eg. caget) in lp:1527636 introduced a bug which cased these short lived clients to crash on exit. This bug should now be fixed.

Server bind issue on Windows

When a National Instruments network variables CA server is already running on a Windows system and an IOC or PCAS server is started, the IOC's attempt to bind a TCP socket to the CA server port number fails, but Windows returns a different error status value than the IOC is expecting in that circumstance (because the National Instruments code requests exclusive use of that port, unlike the EPICS code) so the IOC fails to start properly. The relevent EPICS bind() checks have now been updated so the IOC will request that a dynamic port number be allocated for this TCP socket instead when this happens.

Checking Periodic Scan Rates

Code has been added to the IOC startup to better protect it against bad periodic scan rates, including against locales where . is not accepted as a decimal separator character. If the scan period in a menuScan choice string cannot be parsed, the associated periodic scan thread will no longer be started by the IOC and a warning message will be displayed at iocInit time. The scanppl command will also flag the faulty menuScan value.

Changes made between 3.15.4 and 3.15.5

dbStatic Library Speedup and Cleanup

Loading of database files has been optimized to avoid overproportionally long loading times for large databases. As a part of this, the alphabetical ordering of records instances (within a record type) has been dropped. In the unexpected case that applications were relying on the alphabetic order, setting dbRecordsAbcSorted = 1 before loading the databases will retain the old behavior.

The routine dbRenameRecord() has been removed, as it was intended to be used by database configuration tools linked against a host side version of the dbStatic library that is not being built anymore.

Launchpad Bug-fixes

In addition to the more detailed change descriptions below, the following Launchpad bugs have also been fixed in this release:

Whole-Program Optimization for MS Visual Studio Targets

When using the Microsoft compilers a new build system variable is provided that controls whether whole program optimization is used or not. For static builds using Visual Studio 2010 this optimization must be disabled. This is controlled in the files configure/os/ and configure/os/CONFIG_SITE.Common.win32-x86-static by setting the variable OPT_WHOLE_PROGRAM = NO to override the default value YES that would otherwise be used.

Note that enabling this optimization slows down the build process. It is not possible to selectively disable this optimization, when building a particular module say; Microsoft's linker will restart itself automatically with the -LTCG flag set and display a warning if it is asked to link any object files that were compiled with the -GL flag.

Add dynamic (variable length) array support to PCAS

Dynamic array sizing support was added to the IOC server (RSRV) in the Base-3.14.12 release, but has not until now been supported in the Portable Channel Access Server (PCAS). Channel Access server applications using the PCAS may not need to be modified at all; if they already push monitors with different gdd array lengths, those variable sizes will be forwarded to any CA clients who have requested variable length updates. The example CAS server application has been modified to demonstrate this feature.

In implementing the above, the gdd method gdd::put(const gdd *) now copies the full-sized array from the source gdd if the destination gdd is of type array, has no allocated memory and a boundary size of 0.

Additional epicsTime conversion

The EPICS timestamp library (epicsTime) inside libCom's OSI layer has been extended by routines that convert from struct tm to the EPICS internal epicsTime type, assuming UTC - i.e. without going through the timezone mechanism. This solves issues with converting from the structured type to the EPICS timestamp at driver level from multiple threads at a high repetition rate, where the timezone mechanism was blocking on file access.

MinGW Cross-builds from Linux

The build configuration files that allow cross-building of the 32-bit win32-x86-mingw cross-target have been adjusted to default to building shared libraries (DLLs) as this is now supported by recent MinGW compilers. The 64-bit windows-x64-mingw cross-target was already being built that way by default. The configuration options to tell the minGW cross-compiler to link programs with static versions of the compiler support libraries have now been moved into the files.

General Time updates

The iocInit code now performs a sanity check of the current time returned by the generalTime subsystem and will print a warning if the wall-clock time returned has not been initialized yet. This is just a warning message; when a time provider does synchonize the IOC will subsequently pick up and use the correct time. This check code also primes the registered event system provider if there is one so the epicsTimeGetEventInt() routine will work on IOCs that ask for event time within an interrupt service routine.

The osiClockTime provider's synchronization thread (which is only used on some embedded targets) will now poll the other time providers at 1Hz until the first time it manages to get a successful timestamp, after which it will poll for updates every 60 seconds as before.

The routine generalTimeGetExceptPriority() was designed for use by backup (lower priority) time providers like the osiClockTime provider which do not have their own absolute time reference and rely on other providers for an absolute time source. This routine no longer implements the ratchet mechanism that prevented the time it returned from going backwards. If the backup clock's tick-timer runs fast the synchronization of the backup time provider would never allow it to be corrected backwards when the ratchet was in place. The regular epicsTimeGetCurrent() API still uses the ratchet mechanism, so this change will not cause the IOC to see time going backwards.

Microsoft Visual Studio builds

The build configuration files for builds using the Microsoft compilers have been updated, although there should be no noticable difference at most sites. One extra compiler warning is now being suppressed for C++ code, C4344: behavior change: use of explicit template arguments results in ... which is gratuitous and was appearing frequently in builds of the EPICS V4 modules.

Cross-builds of the windows-x64 target from a win32-x86 host have been removed as they don't actually work within the context of a single make run. Significant changes to the build configuration files would be necessary for these kinds of cross-builds to work properly, which could be done if someone needs them (email Andrew Johnson before working on this, and see this stack-overflow answer for a starting point).

Bazaar keywords such as 'Revision-Id' removed

In preparation for moving to git in place of the Bazaar revision control system we have removed all the keywords from the Base source code.

Linux systemd service file for CA Repeater

Building this version of Base on a Linux system creates a systemd service file suitable for starting the Channel Access Repeater under systemd. The file will be installed into the target bin directory, from where it can be copied into the appropriate systemd location and modified as necessary. Installation instructions are included as comments in the file.

Changes made between 3.15.3 and 3.15.4

New string input device support "getenv"

A new "getenv" device support for both the stringin and lsi (long string input) record types can be used to read the value of an environment variable from the IOC at runtime. See base/db/softIocExit.db for sample usage.

Build rules and DELAY_INSTALL_LIBS

A new order-only prerequisite build rule has been added to ensure that library files (and DLL stubs on Windows) get installed before linking any executables, which resolves parallel build problems on high-powered CPUs. There are some (rare) cases though where a Makefile has to build an executable and run it to be able to compile code for a library built by the same Makefile. With this new build rule GNUmake will complain about a circular dependency and the build will probably fail in those cases. To avoid this problem the failing Makefile should set DELAY_INSTALL_LIBS = YES before including the $(TOP)/configure/RULES file, disabling the new build rule.

IOC environment variables and build parameters

The IOC now sets a number of environment variables at startup that provide the version of EPICS Base it was built against (EPICS_VERSION_...) and its build architecture (ARCH). In some cases this allows a single iocBoot/ioc directory to be used to run the same IOC on several different architectures without any changes.

There are also 3 new environment parameters (EPICS_BUILD_...) available that C/C++ code can use to find out the target architecture, OS class and compiler class it was built with. These may be useful when writing interfaces to other languages.

New implementation of promptgroup/gui_group field property

The mechanism behind the "promptgroup()" field property inside a record type definition has been changed. Instead of using a fixed set of choices, the static database access library now collects the used gui group names while parsing DBD information. Group names should start with a two-digit number plus space-dash-space to allow proper sorting of groups.

The include file guigroup.h that defined the fixed set of choices has been deprecated. Instead, use the conversion functions between index number and group string that have been added to dbStaticLib.

When a DBD file containing record-type descriptions is expanded, any old-style GUI_xxx group names will be replaced by a new-style string for use by the IOC. This permits an older record type to be used with the 3.15.4 release, although eventually record types should be converted by hand with better group names used.

CA server configuration changes

RSRV now honors EPICS_CAS_INTF_ADDR_LIST and binds only to the provided list of network interfaces. Name searches (UDP and TCP) on other network interfaces are ignored. For example on a computer with interfaces,, and, setting "EPICS_CAS_INTF_ADDR_LIST=''" will accept traffic on the .1.1 and .2.1, but ignore from .3.1

RSRV now honors EPICS_CAS_IGNORE_ADDR_LIST and ignores UDP messages received from addresses in this list.

Previously, CA servers (RSRV and PCAS) would build the beacon address list using EPICS_CA_ADDR_LIST if EPICS_CAS_BEACON_ADDR_LIST was no set. This is no longer done. Sites depending on this should set both envronment variables to the same value.

IPv4 multicast for name search and beacons

libca, RSRV, and PCAS may now use IPv4 multicasting for UDP traffic (name search and beacons). This is disabled by default. To enable multicast address(s) must be listed in EPICS_CA_ADDR_LIST for clients and EPICS_CAS_INTF_ADDR_LIST for servers (IOCs should set both). For example: "EPICS_CAS_INTF_ADDR_LIST='' EPICS_CA_ADDR_LIST=".

Please note that no IPv4 multicast address is officially assigned for Channel Access by IANA. The example is taken from the AD-HOC Block I range.

Moved mlockall() into its own epicsThread routine

Since EPICS Base on Posix OSs the initialization of the epicsThread subsystem has called mlockall() when the OS supports it and thread priority scheduling is enabled. Doing so has caused problems in third-party applications that call the CA client library, so the functionality has been moved to a separate routine epicsThreadRealtimeLock() which will be called by the IOC at iocInit (unless disabled by setting the global variable dbThreadRealtimeLock to zero).

Added dbQuietMacroWarnings control

When loading database files, macros get expanded even on comment lines. If a comment contains an undefined macro, the load still continues but an error message gets printed. For this release the error message has been changed to a warning, but even this warning can be made less verbose by setting this new variable to a non-zero value before loading the file, like this:

var dbQuietMacroWarnings 1      iocsh
dbQuietMacroWarnings=1          VxWorks

This was Launchpad bug 541119.

Changes from the 3.14 branch between 3.15.3 and 3.15.4

NTP Time Provider adjusts to OS tick rate changes

Dirk Zimoch provided code that allows the NTP Time provider (used on VxWorks and RTEMS only) to adapt to changes in the OS clock tick rate after the provider has been initialized. Note that changing the tick rate after iocInit() is not advisable, and that other software might still misbehave if initialized before an OS tick rate change. This change was back-ported from the 3.15 branch.

Making IOC ca_get operations atomic

When a CA client gets data from an IOC record using a compound data type such as DBR_TIME_DOUBLE the value field is fetched from the database in a separate call than the other metadata, without keeping the record locked. This allows some other thread such as a periodic scan thread a chance to interrupt the get operation and process the record in between. CA monitors have always been atomic as long as the value data isn't a string or an array, but this race condition in the CA get path has now been fixed so the record will stay locked between the two fetch operations.

This fixes Launchpad bug #1581212, thanks to Till Strauman and Dehong Zhang.

New CONFIG_SITE variable for running self-tests

The 'make runtests' and 'make tapfiles' build targets normally only run the self-tests for the main EPICS_HOST_ARCH architecture. If the host is able to execute self-test programs for other target architectures that are being built by the host, such as when building a -debug version of the host architecture for example, the names of those other architectures can be added to the new CROSS_COMPILER_RUNTEST_ARCHS variable in either the configure/CONFIG_SITE file or in an appropriate configure/os/CONFIG_SITE.<host>.Common file to have the test programs for those targets be run as well.

Additional RELEASE file checks

An additional check has been added at build-time for the contents of the configure/RELEASE file(s), which will mostly only affect users of the Debian EPICS packages published by NSLS-2. Support modules may share an install path, but all such modules must be listed adjacent to each other in any RELEASE files that point to them. For example the following will fail the new checks:

AUTOSAVE = /usr/lib/epics
ASYN = /home/mdavidsaver/asyn
EPICS_BASE = /usr/lib/epics

giving the compile-time error

This application's RELEASE file(s) define
	EPICS_BASE = /usr/lib/epics
after but not adjacent to
	AUTOSAVE = /usr/lib/epics
Module definitions that share paths must be grouped together.
Either remove a definition, or move it to a line immediately
above or below the other(s).
Any non-module definitions belong in configure/CONFIG_SITE.

In many cases such as the one above the order of the AUTOSAVE and ASYN lines can be swapped to let the checks pass, but if the AUTOSAVE module depended on ASYN and hence had to appear before it in the list this error indicates that AUTOSAVE should also be built in its own private area; a shared copy would likely be incompatible with the version of ASYN built in the home directory.

String field buffer overflows

Two buffer overflow bugs that can crash the IOC have been fixed, caused by initializing a string field with a value larger than the field size (Launchpad bug #1563191).

Fixed stack corruption bug in epicsThread C++ API

The C++ interface to the epicsThread API could corrupt the stack on thread exit in some rare circumstances, usually at program exit. This bug has been fixed (Launchpad bug #1558206).

RTEMS NTP Support Issue

On RTEMS the NTP Time Provider could in some circumstances get out of sync with the server because the osdNTPGet() code wasn't clearing its input socket before sending out a new request. This (Launchpad bug 1549908) has now been fixed.

CALC engine bitwise operator fixes

The bitwise operators in the CALC engine have been modified to work properly with values that have bit 31 (0x80000000) set. This modification involved back-porting some earlier changes from the 3.15 branch, and fixes Launchpad bug #1514520.

Fix ipAddrToAsciiAsync(): Don't try to join the daemon thread

On process exit, don't try to stop the worker thread that makes DNS lookups asynchronous. Previously this would wait for any lookups still in progress, delaying the exit unnecessarily. This was most obvious with catools (eg. cainfo). lp:1527636

Fix epicsTime_localtime() on Windows

Simpler versions of the epicsTime_gmtime() and epicsTime_localtime() routines have been included in the Windows implementations, and a new test program added. The original versions do not report DST status properly. Fixes Launchpad bug 1528284.