1 files changed, 9 insertions, 5 deletions

diff --git a/gl/warn-on-use.h b/gl/warn-on-use.h
index 30756034..c0072412 100644
--- a/gl/warn-on-use.h
+++ b/gl/warn-on-use.h
@@ -1,5 +1,5 @@
 /* A C macro for emitting warnings if a function is used.
-   Copyright (C) 2010-2023 Free Software Foundation, Inc.
+   Copyright (C) 2010-2025 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify it
    under the terms of the GNU Lesser General Public License as published
@@ -32,6 +32,10 @@
    _GL_WARN_ON_USE_ATTRIBUTE is for functions with 'static' or 'inline'
    linkage.
 
+   _GL_WARN_ON_USE should not be used more than once for a given function
+   in a given compilation unit (because this may generate a warning even
+   if the function is never called).
+
    However, one of the reasons that a function is a portability trap is
    if it has the wrong signature.  Declaring FUNCTION with a different
    signature in C is a compilation error, so this macro must use the
@@ -81,7 +85,7 @@
    */
 #ifndef _GL_WARN_ON_USE
 
-# if 4 < __GNUC__ || (__GNUC__ == 4 && 3 <= __GNUC_MINOR__)
+# if (4 < __GNUC__ || (__GNUC__ == 4 && 3 <= __GNUC_MINOR__)) && !defined __clang__
 /* A compiler attribute is available in gcc versions 4.3.0 and later.  */
 #  define _GL_WARN_ON_USE(function, message) \
 _GL_WARN_EXTERN_C __typeof__ (function) function __attribute__ ((__warning__ (message)))
@@ -94,7 +98,7 @@ _GL_WARN_EXTERN_C __typeof__ (function) function \
   __attribute__ ((__diagnose_if__ (1, message, "warning")))
 #  define _GL_WARN_ON_USE_ATTRIBUTE(message) \
   __attribute__ ((__diagnose_if__ (1, message, "warning")))
-# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
+# elif (__GNUC__ >= 3 || defined __clang__) && GNULIB_STRICT_CHECKING
 /* Verify the existence of the function.  */
 #  define _GL_WARN_ON_USE(function, message) \
 _GL_WARN_EXTERN_C __typeof__ (function) function
@@ -117,7 +121,7 @@ _GL_WARN_EXTERN_C int _gl_warn_on_use
 #  define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
      _GL_WARN_ON_USE (function, msg)
 # else
-#  if 4 < __GNUC__ || (__GNUC__ == 4 && 3 <= __GNUC_MINOR__)
+#  if (4 < __GNUC__ || (__GNUC__ == 4 && 3 <= __GNUC_MINOR__)) && !defined __clang__
 /* A compiler attribute is available in gcc versions 4.3.0 and later.  */
 #   define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
 extern rettype_gcc function parameters_and_attributes \
@@ -127,7 +131,7 @@ extern rettype_gcc function parameters_and_attributes \
 #   define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
 extern rettype_clang function parameters_and_attributes \
   __attribute__ ((__diagnose_if__ (1, msg, "warning")))
-#  elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
+#  elif (__GNUC__ >= 3 || defined __clang__) && GNULIB_STRICT_CHECKING
 /* Verify the existence of the function.  */
 #   define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
 extern rettype_gcc function parameters_and_attributes