Re: need to define _ISOC99_SOURCE

[Bruno Haible <haible at ilog dot fr>]

Paul Eggert writes:
> Instead, GNU applications
> use autoconf to find out what functions are available.  GNU
> applications don't want to be limited to using only the POSIX
> functions; they want to run well on their target host, and exploit its
> extra features.  The GNU C library should support this.

For GNU applications, this can easily be fixed in the framework of
autoconf:

We already have a macro AC_AIX which defines _ALL_SOURCE to get access
to all reasonable API functions on AIX.

There ought to exist a macro AC_HPUX which defines _HPUX_SOURCE to get
access to all API functions on HP-UX.

There also ought to exist a macro AC_GNU which defines _GNU_SOURCE to
get access to all reasonable API functions in GNU libc.
  - mempcpy and stpcpy in <string.h>,
  - wcwidth in <wchar.h>. (This one could also be done via
    _XOPEN_SOURCE=500 but Paul Eggert says this should be avoided
    because it causes havoc on Solaris.)

Akim, what about two new autoconf macros? <grin>

Besides that, I agree with Ulrich, that it would cause complications
to mix a pre-C99 compiler (without features like \uNNNN in strings,
true/false support in C preprocessor expressions, or _Complex) with a C99
library. It is really gcc which ought to switch on C99 extensions on
by default in the next release.

Bruno