Обсуждение: Q: How to #ifdef for dlopen() or a specific OS Version

For a patch to fix the AIX port I would like to differentiate
Versions below 4.3 and above, or rather I would like to 
differentiate whether -ldl has dlopen().

A compiler define would be _AIX43, but I guess we are supposed to 
use a define from configure.

Thanks
Andreas

Zeugswetter Andreas SB <ZeugswetterA@wien.spardat.at> writes:
> For a patch to fix the AIX port I would like to differentiate
> Versions below 4.3 and above, or rather I would like to 
> differentiate whether -ldl has dlopen().

Checking the latter condition seems more robust.

It's not hard.  After configure.in's line

AC_CHECK_LIB(dl,       main)

you could add something like

AC_CHECK_LIB(dl, dlopen, [AC_DEFINE(HAVE_DLOPEN_IN_LIBDL)])

and make the corresponding addition to config.h.in and/or
Makefile.global.in, depending on whether you need access to this symbol
from C code, Makefiles, or both.
        regards, tom lane