[libcxx-commits] [libcxx] 906e3ec - [AIX][libc++] Forward-declare locale functions in aix.h when _XOPEN_SOURCE < 700 (#220508)

[via libcxx-commits]

Author: Himadhith
Date: 2026-10-07T02:53:13Z
New Revision: 906e3ec0647aef01363973edf3cb0104a812589a

URL: https://github.com/llvm/llvm-project/commit/906e3ec0647aef01363973edf3cb0104a812589a
DIFF: https://github.com/llvm/llvm-project/commit/906e3ec0647aef01363973edf3cb0104a812589a.diff

LOG: [AIX][libc++] Forward-declare locale functions in aix.h when _XOPEN_SOURCE < 700 (#220508)

On AIX, the following locale function `uselocale` is only declared in
`usr/include/locale.h` when `_XOPEN_SOURCE > 700`.

This causes a failure in the test
`libcxx/test/extensions/posix/xopen_source.gen.py` which tests
`_XOPEN_SOURCE ` against 500, 600 and 700, with the following error:
```
#__locale_dir/support/aix.h:36:72: error: no member named 'uselocale' in the global namespace; did you mean 'setlocale'?
```

The fix here is to forward declare `uselocale` inside `aix.h` and make
it visible.

---------

Co-authored-by: himadhith <himadhith.v at ibm.com>

Added: 
    

Modified: 
    libcxx/include/__locale_dir/support/aix.h
    libcxx/test/extensions/posix/xopen_source.gen.py

Removed: 
    


################################################################################
diff  --git a/libcxx/include/__locale_dir/support/aix.h b/libcxx/include/__locale_dir/support/aix.h
index 17f095ac6ce424..ef2194eb2dff9b 100644
--- a/libcxx/include/__locale_dir/support/aix.h
+++ b/libcxx/include/__locale_dir/support/aix.h
@@ -32,12 +32,15 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace __locale {
 
+// Forward declare for _XOPEN_SOURCE=500 and _XOPEN_SOURCE=600
+extern "C" locale_t __libcpp_aix_uselocale(locale_t) _NOEXCEPT __asm__("uselocale");
+
 struct __locale_guard {
-  _LIBCPP_HIDE_FROM_ABI __locale_guard(locale_t __loc) : __old_loc_(::uselocale(__loc)) {}
+  _LIBCPP_HIDE_FROM_ABI __locale_guard(locale_t __loc) : __old_loc_(__libcpp_aix_uselocale(__loc)) {}
 
   _LIBCPP_HIDE_FROM_ABI ~__locale_guard() {
     if (__old_loc_)
-      ::uselocale(__old_loc_);
+      __libcpp_aix_uselocale(__old_loc_);
   }
 
   locale_t __old_loc_;

diff  --git a/libcxx/test/extensions/posix/xopen_source.gen.py b/libcxx/test/extensions/posix/xopen_source.gen.py
index ac04e38bde38a5..bd14e691de5af1 100644
--- a/libcxx/test/extensions/posix/xopen_source.gen.py
+++ b/libcxx/test/extensions/posix/xopen_source.gen.py
@@ -12,10 +12,6 @@
 #
 # https://llvm.org/PR117630
 
-# The AIX localization support uses some functions as part of their headers that require a
-# recent value of _XOPEN_SOURCE.
-# UNSUPPORTED: LIBCXX-AIX-FIXME
-
 # FreeBSD maps _XOPEN_SOURCE=500 to __ISO_C_VISIBLE=1990 (see <sys/_visible.h>), which hides
 # everything C99 added to the C library, even in C++ mode. libc++ needs some of those
 # additions to provide a conforming library at all.