On 09/26/2012 06:24 AM, Adrian Bunk wrote:
> You assume gnu99 will always include all features of gnu11?
Yes. I don't see why it wouldn't. C11 is not incompatible
with C99, the way that C99 was incompatible with C89.
(Again, except for 'gets'.)
As I understand it, the scenario you're worried about is that if a
package really needs C11 features that -std=gnu99 would disable in
future hypothetical versions of GCC, and if the package's builder
then runs 'configure CC="gcc -std=gnu99"', then AC_PROG_CC won't
replace that '-std=gnu99' with '-std=gnu11'. But this scenario
is so implausible that surely we need not worry about it. Or
possibly I'm misunderstanding you....
> - currently gcc >= 4.7 is the only compiler supported for that in
> autoconf
True, but I just now pushed this for IBM XL C. And it will come
in the other compilers.
>From 97e027a8f736c9754212607cb01f87a5997699b0 Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Wed, 26 Sep 2012 07:49:59 -0700
Subject: [PATCH] AC_PROG_CC: try -qlanglvl=extc1x, for IBM XL C V12.1
* lib/autoconf/c.m4 (_AC_PROG_CC_C11): Add -qlanglvl=extc1x, for
IBM XL C V12.1. It shouldn't pass the C11 test yet, since it's not
documented to support _Alignas, _Alignof, UTF-8 string literals,
and duplicate typedefs, but presumably it will eventually.
---
lib/autoconf/c.m4 | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/lib/autoconf/c.m4 b/lib/autoconf/c.m4
index 808c104..0309416 100644
--- a/lib/autoconf/c.m4
+++ b/lib/autoconf/c.m4
@@ -1347,7 +1347,7 @@ AC_DEFUN([_AC_PROG_CC_C99],
[_AC_C_C99_TEST_BODY],
dnl Try
dnl GCC -std=gnu99 (unused restrictive modes: -std=c99
-std=iso9899:1999)
-dnl AIX -qlanglvl=extc99 (unused restrictive mode:
-qlanglvl=stdc99)
+dnl IBM XL C -qlanglvl=extc99 (unused restrictive mode: -qlanglvl=stdc99)
dnl HP cc -AC99
dnl Intel ICC -std=c99, -c99 (deprecated)
dnl IRIX -c99
@@ -1432,8 +1432,9 @@ struct anonymous
]],
dnl Try
dnl GCC -std=gnu11 (unused restrictive mode: -std=c11)
+dnl IBM XL C -qlanglvl=extc1x (no extc11 or (unused) stdc11 in V12.1)
dnl with extended modes being tried first.
-[[-std=gnu11]], [$1], [$2])[]dnl
+[[-std=gnu11 -qlanglvl=extc1x]], [$1], [$2])[]dnl
])# _AC_PROG_CC_C11
@@ -1740,7 +1741,7 @@ AC_DEFUN([AC_C_CONST],
/* NEC SVR4.0.2 mips cc rejects this. */
struct point {int x, y;};
static struct point const zero = {0,0};
- /* AIX XL C 1.02.0.0 rejects this.
+ /* IBM XL C 1.02.0.0 rejects this.
It does not let you subtract one const X* pointer from another in
an arm of an if-expression whose if-part is not a constant
expression */
@@ -1768,7 +1769,7 @@ AC_DEFUN([AC_C_CONST],
iptr p = 0;
++p;
}
- { /* AIX XL C 1.02.0.0 rejects this sort of thing, saying
+ { /* IBM XL C 1.02.0.0 rejects this sort of thing, saying
"k.c", line 2.27: 1506-025 (S) Operand must be a modifiable lvalue. */
struct s { int j; const int *ap[3]; } bx;
struct s *b = &bx; b->j = 5;
@@ -2064,7 +2065,7 @@ AC_DEFUN([AC_OPENMP],
dnl Intel C -openmp
dnl SGI C, PGI C -mp
dnl Tru64 Compaq C -omp
- dnl IBM C (AIX, Linux) -qsmp=omp
+ dnl IBM XL C (AIX, Linux) -qsmp=omp
dnl Cray CCE -homp
dnl NEC SX -Popenmp
dnl Lahey Fortran (Linux) --openmp
--
1.7.11.4
