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-rw-r--r--tests/warn-on-use.h122
1 files changed, 81 insertions, 41 deletions
diff --git a/tests/warn-on-use.h b/tests/warn-on-use.h
index e76c384..94f5b92 100644
--- a/tests/warn-on-use.h
+++ b/tests/warn-on-use.h
@@ -1,17 +1,17 @@
/* A C macro for emitting warnings if a function is used.
- Copyright (C) 2010-2018 Free Software Foundation, Inc.
+ Copyright (C) 2010-2022 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3 of the License, or
+ under the terms of the GNU Lesser General Public License as published
+ by the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU General Public License
+ You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* _GL_WARN_ON_USE (function, "literal string") issues a declaration
@@ -20,23 +20,32 @@
supported by the compiler. If the compiler does not support this
feature, the macro expands to an unused extern declaration.
- This macro is useful for marking a function as a potential
+ _GL_WARN_ON_USE_ATTRIBUTE ("literal string") expands to the
+ attribute used in _GL_WARN_ON_USE. If the compiler does not support
+ this feature, it expands to empty.
+
+ These macros are useful for marking a function as a potential
portability trap, with the intent that "literal string" include
instructions on the replacement function that should be used
- instead. 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 same type as any existing declaration so
- that programs that avoid the problematic FUNCTION do not fail to
- compile merely because they included a header that poisoned the
- function. But this implies that _GL_WARN_ON_USE is only safe to
- use if FUNCTION is known to already have a declaration. Use of
- this macro implies that there must not be any other macro hiding
- the declaration of FUNCTION; but undefining FUNCTION first is part
- of the poisoning process anyway (although for symbols that are
- provided only via a macro, the result is a compilation error rather
- than a warning containing "literal string"). Also note that in
- C++, it is only safe to use if FUNCTION has no overloads.
+ instead.
+ _GL_WARN_ON_USE is for functions with 'extern' linkage.
+ _GL_WARN_ON_USE_ATTRIBUTE is for functions with 'static' or 'inline'
+ linkage.
+
+ 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
+ same type as any existing declaration so that programs that avoid
+ the problematic FUNCTION do not fail to compile merely because they
+ included a header that poisoned the function. But this implies that
+ _GL_WARN_ON_USE is only safe to use if FUNCTION is known to already
+ have a declaration. Use of this macro implies that there must not
+ be any other macro hiding the declaration of FUNCTION; but
+ undefining FUNCTION first is part of the poisoning process anyway
+ (although for symbols that are provided only via a macro, the result
+ is a compilation error rather than a warning containing
+ "literal string"). Also note that in C++, it is only safe to use if
+ FUNCTION has no overloads.
For an example, it is possible to poison 'getline' by:
- adding a call to gl_WARN_ON_USE_PREPARE([[#include <stdio.h>]],
@@ -54,47 +63,78 @@
(less common usage, like &environ, will cause a compilation error
rather than issue the nice warning, but the end result of informing
the developer about their portability problem is still achieved):
- #if HAVE_RAW_DECL_ENVIRON
- static char ***rpl_environ (void) { return &environ; }
- _GL_WARN_ON_USE (rpl_environ, "environ is not always properly declared");
- # undef environ
- # define environ (*rpl_environ ())
- #endif
+ #if HAVE_RAW_DECL_ENVIRON
+ static char ***
+ rpl_environ (void) { return &environ; }
+ _GL_WARN_ON_USE (rpl_environ, "environ is not always properly declared");
+ # undef environ
+ # define environ (*rpl_environ ())
+ #endif
+ or better (avoiding contradictory use of 'static' and 'extern'):
+ #if HAVE_RAW_DECL_ENVIRON
+ static char ***
+ _GL_WARN_ON_USE_ATTRIBUTE ("environ is not always properly declared")
+ rpl_environ (void) { return &environ; }
+ # undef environ
+ # define environ (*rpl_environ ())
+ #endif
*/
#ifndef _GL_WARN_ON_USE
# if 4 < __GNUC__ || (__GNUC__ == 4 && 3 <= __GNUC_MINOR__)
/* A compiler attribute is available in gcc versions 4.3.0 and later. */
# define _GL_WARN_ON_USE(function, message) \
-extern __typeof__ (function) function __attribute__ ((__warning__ (message)))
+_GL_WARN_EXTERN_C __typeof__ (function) function __attribute__ ((__warning__ (message)))
+# define _GL_WARN_ON_USE_ATTRIBUTE(message) \
+ __attribute__ ((__warning__ (message)))
+# elif __clang_major__ >= 4
+/* Another compiler attribute is available in clang. */
+# define _GL_WARN_ON_USE(function, message) \
+_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
/* Verify the existence of the function. */
# define _GL_WARN_ON_USE(function, message) \
-extern __typeof__ (function) function
+_GL_WARN_EXTERN_C __typeof__ (function) function
+# define _GL_WARN_ON_USE_ATTRIBUTE(message)
# else /* Unsupported. */
# define _GL_WARN_ON_USE(function, message) \
_GL_WARN_EXTERN_C int _gl_warn_on_use
+# define _GL_WARN_ON_USE_ATTRIBUTE(message)
# endif
#endif
-/* _GL_WARN_ON_USE_CXX (function, rettype, parameters_and_attributes, "string")
- is like _GL_WARN_ON_USE (function, "string"), except that the function is
- declared with the given prototype, consisting of return type, parameters,
- and attributes.
+/* _GL_WARN_ON_USE_CXX (function, rettype_gcc, rettype_clang, parameters_and_attributes, "message")
+ is like _GL_WARN_ON_USE (function, "message"), except that in C++ mode the
+ function is declared with the given prototype, consisting of return type,
+ parameters, and attributes.
This variant is useful for overloaded functions in C++. _GL_WARN_ON_USE does
not work in this case. */
#ifndef _GL_WARN_ON_USE_CXX
-# if 4 < __GNUC__ || (__GNUC__ == 4 && 3 <= __GNUC_MINOR__)
-# define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
-extern rettype function parameters_and_attributes \
- __attribute__ ((__warning__ (msg)))
-# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
+# if !defined __cplusplus
+# 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__)
+/* 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 \
+ __attribute__ ((__warning__ (msg)))
+# elif __clang_major__ >= 4
+/* Another compiler attribute is available in clang. */
+# 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
/* Verify the existence of the function. */
-# define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
-extern rettype function parameters_and_attributes
-# else /* Unsupported. */
-# define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
+# define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
+extern rettype_gcc function parameters_and_attributes
+# else /* Unsupported. */
+# define _GL_WARN_ON_USE_CXX(function,rettype_gcc,rettype_clang,parameters_and_attributes,msg) \
_GL_WARN_EXTERN_C int _gl_warn_on_use
+# endif
# endif
#endif
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