Re: AC_SYS_LARGEFILE

[Russ Allbery]

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."

-- 
Russ Allbery (eagle@eyrie.org)             <https://www.eyrie.org/~eagle/>