+++ /dev/null
-/* A C macro for emitting warnings if a function is used.
- Copyright (C) 2010-2016 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
- (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.
-
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
-
-/* _GL_WARN_ON_USE (function, "literal string") issues a declaration
- for FUNCTION which will then trigger a compiler warning containing
- the text of "literal string" anywhere that function is called, if
- 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
- 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.
-
- For an example, it is possible to poison 'getline' by:
- - adding a call to gl_WARN_ON_USE_PREPARE([[#include <stdio.h>]],
- [getline]) in configure.ac, which potentially defines
- HAVE_RAW_DECL_GETLINE
- - adding this code to a header that wraps the system <stdio.h>:
- #undef getline
- #if HAVE_RAW_DECL_GETLINE
- _GL_WARN_ON_USE (getline, "getline is required by POSIX 2008, but"
- "not universally present; use the gnulib module getline");
- #endif
-
- It is not possible to directly poison global variables. But it is
- possible to write a wrapper accessor function, and poison that
- (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
- */
-#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)))
-# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
-/* Verify the existence of the function. */
-# define _GL_WARN_ON_USE(function, message) \
-extern __typeof__ (function) function
-# else /* Unsupported. */
-# define _GL_WARN_ON_USE(function, message) \
-_GL_WARN_EXTERN_C int _gl_warn_on_use
-# 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.
- 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
-/* 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) \
-_GL_WARN_EXTERN_C int _gl_warn_on_use
-# endif
-#endif
-
-/* _GL_WARN_EXTERN_C declaration;
- performs the declaration with C linkage. */
-#ifndef _GL_WARN_EXTERN_C
-# if defined __cplusplus
-# define _GL_WARN_EXTERN_C extern "C"
-# else
-# define _GL_WARN_EXTERN_C extern
-# endif
-#endif
projects / debian / gzip / blobdiff