Re: Objections? Re: Checking for CXX libraries -- AC_CXX_CHECK_LIB ?

[Steven G. Johnson]

Sorry to come (very) late to this thread, I was just reading back 
through the archives...

Allan Clark wrote:
> This almost argues for a change to a generic function in AC_CHECK_LIB. 
> Do we ever have a need for an AC_CHECK_LIB() to check C libraries using
> a raw code snippet?  AC_CHECK_LIB(<foo>,functioncall(),...) might have
> some use, but I haven't seen it yet.

I think there is definitely such a need.  What happens is that in some 
library checks (for example, pthreads), you don't know whether the 
function you are testing might be a macro.  In this case, you need to 
#include a header file and write an actual code snippet with the correct 
number (at least) of arguments.  Currently, this means using 
AC_TRY_LINK, which has the disadvantage of requiring manual fiddling 
with $LIBS (and not being cached).

So, rather than doing something specifically for C++, I would advocate a 
more generalized version of AC_CHECK_LIB that, like AC_TRY_LINK, takes 
INCLUDES and FUNCTION-BODY arguments instead of FUNCTION.  (And works 
with whatever the current language is.  This could also be useful for 
Fortran.)

Cordially,
Steven G. Johnson