[libcxx-commits] [libcxx] 91a8753 - [libc++] Skip including langinfo.h when unused (#223749)

[via libcxx-commits]

Author: google-yfyang
Date: 2026-09-16T11:48:10-04:00
New Revision: 91a87531f26b989863517e07f0648733029c7cfe

URL: https://github.com/llvm/llvm-project/commit/91a87531f26b989863517e07f0648733029c7cfe
DIFF: https://github.com/llvm/llvm-project/commit/91a87531f26b989863517e07f0648733029c7cfe.diff

LOG: [libc++] Skip including langinfo.h when unused (#223749)

A previous change unconditionally includes <langinfo.h>.
__get_locale_encoding() only uses langinfo when compiling shared
libraries, and hardcodes "UTF-8" on Android.

glibc's <langinfo.h> defines POSIX nl_item constants as raw numeric
preprocessor macros (#define ERA 46).
This causes Bionic's #define ERA 46 leaks into C++ translation units on
Android and fails the compilation with:

```
error: expected member name or ';' after declaration specifiers
   static constexpr typename ERA = random_value;
```

Added: 
    

Modified: 
    libcxx/include/__locale_dir/support/linux.h

Removed: 
    


################################################################################
diff  --git a/libcxx/include/__locale_dir/support/linux.h b/libcxx/include/__locale_dir/support/linux.h
index 74abf5ab7c598..69f494987e4e3 100644
--- a/libcxx/include/__locale_dir/support/linux.h
+++ b/libcxx/include/__locale_dir/support/linux.h
@@ -17,7 +17,9 @@
 #include <cstdio>
 #include <cstdlib>
 #include <ctype.h>
-#include <langinfo.h>
+#if defined(_LIBCPP_BUILDING_LIBRARY)
+#  include <langinfo.h>
+#endif
 #include <stdarg.h>
 #include <string.h>
 #include <time.h>