Re: readline in base 7.0.7

[Mark Rivers via Core-talk <core-talk at aps.anl.gov>]

Hi Michael,

> As always, I would encourage those interested to follow PRs.

> Compatibility doesn't just happen by itself.

I don't consider myself a core developer, and I can't follow all PRs.  

However, in the past there have been "release candidate" versions of base that were available and announced a few weeks before the official version release date:

corvette:local/epics/base-7.0.6.1>git tag | grep rc

R3.14.10-rc1

R3.14.10-rc2

R3.14.11-rc1

R3.14.12-rc1

R3.14.12.1-rc1

R3.14.12.2-rc1

R3.14.12.3-rc1

R3.14.12.4-rc1

R3.14.12.5-rc1

R3.14.12.6-rc1

R3.14.12.7-rc1

R3.14.12.8-rc1

R3.14.9-rc1

R3.15.1-rc1

R3.15.2-rc1

R3.15.3-rc1

R3.15.4-rc1

R3.15.5-rc1

R3.15.6-rc1

R3.16.1-rc1

R3.16.2-rc1

R7.0.1-rc1

R7.0.2-rc1

R7.0.4.1-rc1

If these were done consistently and announced on core-talk (or better yet on tech-talk) asking people to test them I would try to do so.

Thanks for providing the patch.  I will test it, and if it works then perhaps there should be a 7.0.7.1 relatively soon.

> Specific suggestions on wording are welcomed.  I find it difficult to write succinct documentation which speaks to every user.

I have added the last 2 lines to the release notes below.  I also changed the spelling of "effect" to "affect" in the previous line.

Automatic COMMANDLINE_LIBRARY w/ newer compilers

When built with a compiler supporting __has_include<>, the presence of the <readline/readline.h> will be used to automatically determine a default value for COMMANDLINE_LIBRARY.

Mingw builds with readline support now link -ltermcap instead of -lcurses.

This should not affect sites which set explicitly set COMMANDLINE_LIBRARY as the only definition in Base now has the form COMMANDLINE_LIBRARY ?= ....

However, it does require now manually setting COMMANDLINE_LIBRARY on systems with versions of gcc prior to gcc-5, where previously it was set automatically.  

This includes RHEL/CentOS 6 and 7.

> I don't know when clang or msvc added support.

MSCV added support for __has​_include in VS 2017 15.3.  https://docs.microsoft.com/en-us/cpp/overview/visual-cpp-language-conformance?view=msvc-170

However, I don't think that matters for this readline issue, since the VS studio builds don't use readline, right?

Thanks,

Mark

---

From: Michael Davidsaver <mdavidsaver at gmail.com>
Sent: Friday, September 9, 2022 6:28 PM
To: Mark Rivers <rivers at cars.uchicago.edu>
Cc: core-talk at aps.anl.gov <core-talk at aps.anl.gov>
Subject: Re: readline in base 7.0.7

 

On 9/8/22 11:44, Mark Rivers wrote:
>  > You will need to manually specify COMMANDLINE_LIBRARY for the time being.  (and hopefully put an OS upgrade on your roadmap)
>
> This is unfortunate, since the automatic detection worked fine in base 7.0.6.1.

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

As always, I would encourage those interested to follow PRs.
Compatibility doesn't just happen by itself.


The following lightly tested patch should restore the previous
$(GNU_DIR) automatic detection for older compilers.  (not just
linux)

> diff --git a/configure/toolchain.c b/configure/toolchain.c
> index 2f76b475b..bc37cad64 100644
> --- a/configure/toolchain.c
> +++ b/configure/toolchain.c
> @@ -45,5 +45,7 @@ COMMANDLINE_LIBRARY ?= READLINE
>  COMMANDLINE_LIBRARY ?= EPICS
>  #  endif
>  #else
> -COMMANDLINE_LIBRARY ?= EPICS
> +COMMANDLINE_LIBRARY ?= $(strip $(if $(wildcard \
> +    $(if $(GNU_DIR),$(GNU_DIR)/include/readline/readline.h) \
> +), READLINE, EPICS))
>  #endif


> The release notes really should say that manual editing is now required for older compilers, while it previously was not.

Specific suggestions on wording are welcomed.  I find it
difficult to write succinct documentation which speaks
to every user.


>  They should also say which version of gcc is required to have the automatic detection work.

GCC >=5.0

https://gcc.gnu.org/projects/cxx-status.html#cxx17

I don't know when clang or msvc added support.


>  I now need to spend a few hours rebuilding base and synApps for a bunch of architectures.

I'm sorry to have wasted your time.


>  > and hopefully put an OS upgrade on your roadmap)
>
> We have a number of machines where vendor support for kernel drivers limits such upgrades.  RHEL 7 has 2 more years before EOL, and is still used on many APS beamlines.
>
> Mark
>
> -----Original Message-----
> From: Michael Davidsaver <mdavidsaver at gmail.com>
> Sent: Thursday, September 8, 2022 1:29 PM
> To: Mark Rivers <rivers at cars.uchicago.edu>
> Cc: core-talk at aps.anl.gov
> Subject: Re: readline in base 7.0.7
>
> On 9/8/22 10:40, Mark Rivers via Core-talk wrote:
>
>  > I just built base 7.0.7 on Centos 7 with no changes to the files in configure/os.
>
> Right, I wasn't paying attention.  Automatic detection now depends on GCC version.  As I recall, centos7 has GCC 4.8, which is too old.
>
> You will need to manually specify COMMANDLINE_LIBRARY for the time being.  (and hopefully put an OS upgrade on your roadmap)
>
>  > My IOCs now are not built with libreadline, while in base 7.0.6.1 they were, again with no changes to the configure/os files.
>
>  >
>
>  > I see this change between base 7.0.6.1 and base 7.0.7
>
>  >
>
>  > corvette:base-7.0.7/configure/os>git diff R7.0.6.1 R7.0.7
>
>  > CONFIG_SITE.Common.linux-x
>
>  >
>
>  > CONFIG_SITE.Common.linux-x86        CONFIG_SITE.Common.linux-x86_64
>
>  > CONFIG_SITE.Common.linux-xscale_be
>
>  >
>
>  > corvette:base-7.0.7/configure/os>git diff R7.0.6.1 R7.0.7
>
>  > CONFIG_SITE.Common.linux-x86_64
>
>  >
>
>  > diff --git a/configure/os/CONFIG_SITE.Common.linux-x86_64
>
>  > b/configure/os/CONFIG_SITE.Common.linux-x86_64
>
>  >
>
>  > index e098b76..b98385f 100644
>
>  >
>
>  > --- a/configure/os/CONFIG_SITE.Common.linux-x86_64
>
>  >
>
>  > +++ b/configure/os/CONFIG_SITE.Common.linux-x86_64
>
>  >
>
>  > @@ -15,10 +15,6 @@
>
>  >
>
>  > #    to inform the system of the shared library location.
>
>  >
>
>  > -# Use GNU Readline if the header file is installed
>
>  >
>
>  > -COMMANDLINE_LIBRARY = $(strip $(if $(wildcard \
>
>  >
>
>  > -    $(GNU_DIR)/include/readline/readline.h), READLINE, EPICS))
>
>  >
>
>  > -
>
>  >
>
>  > # If libreadline needs additional libraries to be linked with it, try
>
>  >
>
>  > # uncommenting each of the lines below in turn, starting with the top
>
>  >
>
>  > # one and working downwards, until the build succeeds. Do a 'make rebuild'
>
>  >
>
>  > The release notes say:
>
>  >
>
>  > *Automatic COMMANDLINE_LIBRARY w/ newer compilers*
>
>  >
>
>  > When built with a compiler supporting __has_include<>, the presence of the <readline/readline.h> will be used to automatically determine a default value for COMMANDLINE_LIBRARY.
>
>  >
>
>  > Mingw builds with readline support now link -ltermcap instead of -lcurses.
>
>  >
>
>  > This should not effect sites which set explicitly set COMMANDLINE_LIBRARY as the only definition in Base now has the form COMMANDLINE_LIBRARY ?= ....
>
>  >
>
>  > I interpret the first sentence here to mean that the test for
>
>  > COMMANDLINE_LIBRARY is done in the compiler if possible, but it does
>
>  > not say that the previous way of doing it in the CONFIG_SITE file (for
>
>  > older compilers) has been removed
>
>  >
>
>  > Does this mean that I now need to edit CONFIG_SITE.Common.linux-x86_64 to manually set COMMANDLINE_LIBRARY?
>
>  >
>
>  > Thanks,
>
>  >
>
>  > Mark
>
>  >
>