Experimental Physics and
Industrial Control System

"Dmitry Yu. Bolkhovityanov via Tech-talk" <tech-talk at aps.anl.gov> · Sat, 13 May 2023 13:32:38 +0700 (+07)

Hi Michael,

On Thu, 11 May 2023, Michael Davidsaver wrote:


On 5/11/23 01:38, Dmitry Yu. Bolkhovityanov via Tech-talk wrote:

 ...
 The next step will be to find which git commit bringed this change.


https://github.com/epics-base/epics-base/pull/254



May I suggest a small addition to your patch? It modifies behaviour for

old, non-__has_include()-enabled compilers, thus eliminating a regression

(and solving Mark Rivers' problem mentioned in

https://epics.anl.gov/core-talk/2022/msg00385.php). The idea is to fall

back to old readline detection method instead of defaulting to =EPICS

(the whole file is attached):


% diff -ub ./base-7.0.7/configure/toolchain.c{.orig,}

--- ./base-7.0.7/configure/toolchain.c.orig	2022-09-08 01:50:35.000000000 +0700
+++ ./base-7.0.7/configure/toolchain.c	2023-05-13 13:12:20.967486783 +0700
@@ -45,5 +45,7 @@
 COMMANDLINE_LIBRARY ?= EPICS
 #  endif
 #else
-COMMANDLINE_LIBRARY ?= EPICS
+COMMANDLINE_LIBRARY ?= $(strip $(if $(wildcard \\
+    $(firstword $(READLINE_DIR) $(GNU_DIR))/include/readline/readline.h), \\
+  READLINE, EPICS))
 #endif


The detection snippet was copied from

configure/os/CONFIG_SITE.Common.linux-arm as it tries 2 dirs instead of 1

as most other places do.



I've tested it on CentOS-7.3 (gcc version 4.8.5 20150623) and now

libCom.so.3.22.0 does get a libreadline.so dependency.

(However, as I don't have access to neither vxWorks/RTEMS nor MinGW etc.,

can't check behaviour on such systems.)




 The only oddity which puzzled me is integration of commandline editing
 into libCom -- that looks completely out of place.


Hardly the only historical oddity in a ~30 year old code base.

(at least we don't link in libX11 ...)



As funny as linking in libX11 looks, there could be a reasonable scenario

for libXt: that can be used as application's main loop, taking care of

file descriptors and timeouts, similarly to fdManager. :)



With best regards,
Dmitry
#ifdef _COMMENT_
/* Extract compiler pre-defined macros as Make variables
 *
 * Expanded as $(INSTALL_CFG)/TOOLCHAIN.$(EPICS_HOST_ARCH).$(T_A)
 *
 * Must be careful not to #include any C definitions
 * into what is really a Makefile snippet
 *
 * cf. https://sourceforge.net/p/predef/wiki/Home/
 */
/* GCC preprocessor drops C comments from output.
 * MSVC preprocessor emits C comments in output
 */
#endif

#if defined(__GNUC__) && !defined(__clang__)
GCC_MAJOR = __GNUC__
GCC_MINOR = __GNUC_MINOR__
GCC_PATCH = __GNUC_PATCHLEVEL__

#elif defined(__clang__)
CLANG_MAJOR = __clang_major__
CLANG_MINOR = __clang_minor__
CLANG_PATCH = __clang_patchlevel__

#elif defined(_MSC_VER)
MSVC_VER = _MSC_VER
#endif

#ifdef __rtems__
#include <rtems/score/cpuopts.h>
#  if __RTEMS_MAJOR__>=5
OS_API = posix
#  else
OS_API = score
#  endif
#endif

#ifdef __has_include
#  if defined(__rtems__) && __RTEMS_MAJOR__<5 && __has_include(<libtecla.h>)
COMMANDLINE_LIBRARY ?= LIBTECLA
#  elif __has_include(<readline/readline.h>)
COMMANDLINE_LIBRARY ?= READLINE
#  else
COMMANDLINE_LIBRARY ?= EPICS
#  endif
#else
COMMANDLINE_LIBRARY ?= $(strip $(if $(wildcard \\
    $(firstword $(READLINE_DIR) $(GNU_DIR))/include/readline/readline.h), \\
  READLINE, EPICS))
#endif


Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System