Re: RFC: AC_DEFINE_REPLACE

[Paul Eggert]

> From: Bruce Korb <address@hidden>
> Date: Tue, 26 Mar 2002 14:26:42 -0800
> 
> #ifndef FUNC_BROKEN
> # define posix_func  func
> #else
> # define posix_func  autoconf_rpl_func
> #endif

Yes, that is more portable.  Though we shouldn't use the "posix_"
prefix, as POSIX itself uses it these days for functions like
posix_madvise.  Perhaps "ac_" or "portable_" would be better.

GNU Emacs does something like that with functions like "open" and
"read".  It uses functions rather than a macros, as the functions are
easier to debug.  For example:

   int
   emacs_open (path, oflag, mode)
        char *path;
        int oflag, mode;
   {
     register int rtnval;

     while ((rtnval = open (path, oflag, mode)) == -1
            && (errno == EINTR));
     return (rtnval);
   }

I think Autoconf would do well to follow in that tradition.  In the
end it is probably the only one that will actually work portably, for
all POSIX functions.

I hope I never have to use it myself, though, as it makes the code
painful to maintain.  For example, when importing code from other
packages I would have to substitute "ac_open" for each instance of
"open".