Re: Problem detecting libsigsegv on gawk 4.0.0 on Solaris 9 Sparc w/Sun Studio 12

[Dagobert Michelsen]

Hi Bruno,

Am 02.07.2011 um 13:56 schrieb Bruno Haible:
> Conclusion: The use of option -Xc effectively removes <ucontext.h> from the
> set of available header files. This is expected because in -Xc mode, only ISO 
> C
> headers should be available.
> 
> But <sigsegv.h> relies on <ucontext.h>, for the definition of some types;
> <sigsegv.h> does not include <ucontext.h> for nothing. If <ucontext.h> is
> unavailable, <sigsegv.h> is unavailable, and the gl_LIBSIGSEGV macro detected
> this correctly.
> 
> In summary:
>  - It is not a bug in Solaris cc, because <ucontext.h> is assumed to be
>    unavailable when compiling with -Xc.
>  - It is not a bug in GNU libsigsegv, because you need features of POSIX
>    outside ISO C to implement catching SIGSEGV.
>  - It is not a bug in gnulib, because the gl_LIBSIGSEGV macro detects that
>    <sigsegv.h> is unavailable.

Ok.

>  - If you want that gawk makes use of libsigsegv, simply don't use -Xc.
>    If I configure gawk with
>       $ ./configure --prefix=$HOME/prefix-solaris9-sparc-cc CC="cc -O 
> -D__STDC__"
>    then libsigsegv is found and used, and I get a gawk program that is linked
>    against libsigsegv:

This does not work for me:

> current9s% more foo.c 
> #include <sigsegv.h>
> current9s% cc -O -D__STDC__ -I/opt/csw/include -c foo.c
> command line: warning: macro redefined: __STDC__
> "/usr/include/sys/ucontext.h", line 68: syntax error before or at: sigset_t
> "/usr/include/ucontext.h", line 48: syntax error before or at: *
> "/usr/include/ucontext.h", line 49: syntax error before or at: *
> "/usr/include/ucontext.h", line 51: syntax error before or at: *
> "/usr/include/ucontext.h", line 52: syntax error before or at: *
> cc: acomp failed for foo.c

However, this simple example works with -features=extensions:

> current9s% cc -O -features=extensions -I/opt/csw/include -c foo.c

But not if __STDC__ is set at the same time:

> current9s% cc -O -D__STDC__ -features=extensions -I/opt/csw/include -c foo.c
> command line: warning: macro redefined: __STDC__
> "/usr/include/sys/ucontext.h", line 68: syntax error before or at: sigset_t
> "/usr/include/ucontext.h", line 48: syntax error before or at: *
> "/usr/include/ucontext.h", line 49: syntax error before or at: *
> "/usr/include/ucontext.h", line 51: syntax error before or at: *
> "/usr/include/ucontext.h", line 52: syntax error before or at: *
> cc: acomp failed for foo.c
> current9s% cc -O -D__STDC__=1 -features=extensions -I/opt/csw/include -c foo.c
> command line: warning: macro redefined: __STDC__
> "/usr/include/sys/ucontext.h", line 68: syntax error before or at: sigset_t
> "/usr/include/ucontext.h", line 48: syntax error before or at: *
> "/usr/include/ucontext.h", line 49: syntax error before or at: *
> "/usr/include/ucontext.h", line 51: syntax error before or at: *
> "/usr/include/ucontext.h", line 52: syntax error before or at: *
> cc: acomp failed for foo.c

Maybe the test in awk.h is too strict and should be something like this?
With this patch libsigsegv is properly detected and I get a clean compile
and a passing testsuite with "-features=extensions" added to CFLAGS:

> From 024f67d496160ea6fe8b60b67f4832fed04fd199 Mon Sep 17 00:00:00 2001
> From: Dagobert Michelsen <address@hidden>
> Date: Thu, 7 Jul 2011 17:14:06 +0200
> Subject: [PATCH] Be not that strict on standard
> 
> ---
>  awk.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/awk.h b/awk.h
> index 25abf41..5034a46 100644
> --- a/awk.h
> +++ b/awk.h
> @@ -60,7 +60,7 @@
>  #endif /* LOCALEDIR */
>  #endif
>  
> -#if !defined(__STDC__) || __STDC__ < 1
> +#if (!defined(__STDC__) || __STDC__ < 1) && !defined(__EXTENSIONS__)
>  #error "gawk no longer supports non-C89 environments (no __STDC__ or 
> __STDC__ < 1)"
>  #endif
>  
> -- 
> 1.7.6

The patch is also browsable/downloadable here if necessary:
  
http://sourceforge.net/apps/trac/gar/browser/csw/mgar/pkg/gawk/trunk/files/0001-Be-not-that-strict-on-standard.patch


Best regards

  -- Dago


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