Re: AC_SYS_LARGEFILE

[Sébastien Hinderer]

Many thanks for the message below which I found enlighetning.

Seb.

Russ Allbery (2023/09/11 11:23 -0700):
> Nick Bowler <nbowler@draconx.ca> writes:
>
> > Looking at the code, CC is modified only if the -n32 option is needed to
> > enable large-file support.  The comments suggest this is required on
> > IRIX.  If large-file support can be enabled by preprocessor macros
> > (which I imagine is the case on all current systems), AC_DEFINE is used.
>
> > It has been this way since the macro was originally added to Autoconf.
> > I can only speculate as to why the original author used CC, but the
> > reason is probably so that you can just take an existing package and
> > just add AC_SYS_LARGEFILE with no other modifications and it will almost
> > certainly work without any major problems.
>
> Back in the day when such flags were common (thankfully largely behind us
> at this point), it was standard practice to put architecture selection
> flags like -n32 into CC, not CFLAGS or CPPFLAGS.  That's because such
> flags are really of a different type than CFLAGS or CPPFLAGS, more akin to
> invoking a different compiler for a different target architecture than the
> normal uses of CFLAGS and CPPFLAGS.
>
> I suspect that the aswer to the original question is "don't worry about
> it, just use AC_SYS_LARGEFILE, because no system you will build on will
> need the CC modification anyway."
>