1: /* C++ compatible function declaration macros.
2: Copyright (C) 2010-2011 Free Software Foundation, Inc.
3:
4: This program is free software: you can redistribute it and/or modify it
5: under the terms of the GNU General Public License as published
6: by the Free Software Foundation; either version 3 of the License, or
7: (at your option) any later version.
8:
9: This program is distributed in the hope that it will be useful,
10: but WITHOUT ANY WARRANTY; without even the implied warranty of
11: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12: General Public License for more details.
13:
14: You should have received a copy of the GNU General Public License
15: along with this program. If not, see <http://www.gnu.org/licenses/>. */
16:
17: #ifndef _GL_CXXDEFS_H
18: #define _GL_CXXDEFS_H
19:
20: /* The three most frequent use cases of these macros are:
21:
22: * For providing a substitute for a function that is missing on some
23: platforms, but is declared and works fine on the platforms on which
24: it exists:
25:
26: #if @GNULIB_FOO@
27: # if !@HAVE_FOO@
28: _GL_FUNCDECL_SYS (foo, ...);
29: # endif
30: _GL_CXXALIAS_SYS (foo, ...);
31: _GL_CXXALIASWARN (foo);
32: #elif defined GNULIB_POSIXCHECK
33: ...
34: #endif
35:
36: * For providing a replacement for a function that exists on all platforms,
37: but is broken/insufficient and needs to be replaced on some platforms:
38:
39: #if @GNULIB_FOO@
40: # if @REPLACE_FOO@
41: # if !(defined __cplusplus && defined GNULIB_NAMESPACE)
42: # undef foo
43: # define foo rpl_foo
44: # endif
45: _GL_FUNCDECL_RPL (foo, ...);
46: _GL_CXXALIAS_RPL (foo, ...);
47: # else
48: _GL_CXXALIAS_SYS (foo, ...);
49: # endif
50: _GL_CXXALIASWARN (foo);
51: #elif defined GNULIB_POSIXCHECK
52: ...
53: #endif
54:
55: * For providing a replacement for a function that exists on some platforms
56: but is broken/insufficient and needs to be replaced on some of them and
57: is additionally either missing or undeclared on some other platforms:
58:
59: #if @GNULIB_FOO@
60: # if @REPLACE_FOO@
61: # if !(defined __cplusplus && defined GNULIB_NAMESPACE)
62: # undef foo
63: # define foo rpl_foo
64: # endif
65: _GL_FUNCDECL_RPL (foo, ...);
66: _GL_CXXALIAS_RPL (foo, ...);
67: # else
68: # if !@HAVE_FOO@ or if !@HAVE_DECL_FOO@
69: _GL_FUNCDECL_SYS (foo, ...);
70: # endif
71: _GL_CXXALIAS_SYS (foo, ...);
72: # endif
73: _GL_CXXALIASWARN (foo);
74: #elif defined GNULIB_POSIXCHECK
75: ...
76: #endif
77: */
78:
79: /* _GL_EXTERN_C declaration;
80: performs the declaration with C linkage. */
81: #if defined __cplusplus
82: # define _GL_EXTERN_C extern "C"
83: #else
84: # define _GL_EXTERN_C extern
85: #endif
86:
87: /* _GL_FUNCDECL_RPL (func, rettype, parameters_and_attributes);
88: declares a replacement function, named rpl_func, with the given prototype,
89: consisting of return type, parameters, and attributes.
90: Example:
91: _GL_FUNCDECL_RPL (open, int, (const char *filename, int flags, ...)
92: _GL_ARG_NONNULL ((1)));
93: */
94: #define _GL_FUNCDECL_RPL(func,rettype,parameters_and_attributes) \
95: _GL_FUNCDECL_RPL_1 (rpl_##func, rettype, parameters_and_attributes)
96: #define _GL_FUNCDECL_RPL_1(rpl_func,rettype,parameters_and_attributes) \
97: _GL_EXTERN_C rettype rpl_func parameters_and_attributes
98:
99: /* _GL_FUNCDECL_SYS (func, rettype, parameters_and_attributes);
100: declares the system function, named func, with the given prototype,
101: consisting of return type, parameters, and attributes.
102: Example:
103: _GL_FUNCDECL_SYS (open, int, (const char *filename, int flags, ...)
104: _GL_ARG_NONNULL ((1)));
105: */
106: #define _GL_FUNCDECL_SYS(func,rettype,parameters_and_attributes) \
107: _GL_EXTERN_C rettype func parameters_and_attributes
108:
109: /* _GL_CXXALIAS_RPL (func, rettype, parameters);
110: declares a C++ alias called GNULIB_NAMESPACE::func
111: that redirects to rpl_func, if GNULIB_NAMESPACE is defined.
112: Example:
113: _GL_CXXALIAS_RPL (open, int, (const char *filename, int flags, ...));
114: */
115: #define _GL_CXXALIAS_RPL(func,rettype,parameters) \
116: _GL_CXXALIAS_RPL_1 (func, rpl_##func, rettype, parameters)
117: #if defined __cplusplus && defined GNULIB_NAMESPACE
118: # define _GL_CXXALIAS_RPL_1(func,rpl_func,rettype,parameters) \
119: namespace GNULIB_NAMESPACE \
120: { \
121: rettype (*const func) parameters = ::rpl_func; \
122: } \
123: _GL_EXTERN_C int _gl_cxxalias_dummy
124: #else
125: # define _GL_CXXALIAS_RPL_1(func,rpl_func,rettype,parameters) \
126: _GL_EXTERN_C int _gl_cxxalias_dummy
127: #endif
128:
129: /* _GL_CXXALIAS_RPL_CAST_1 (func, rpl_func, rettype, parameters);
130: is like _GL_CXXALIAS_RPL_1 (func, rpl_func, rettype, parameters);
131: except that the C function rpl_func may have a slightly different
132: declaration. A cast is used to silence the "invalid conversion" error
133: that would otherwise occur. */
134: #if defined __cplusplus && defined GNULIB_NAMESPACE
135: # define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \
136: namespace GNULIB_NAMESPACE \
137: { \
138: rettype (*const func) parameters = \
139: reinterpret_cast<rettype(*)parameters>(::rpl_func); \
140: } \
141: _GL_EXTERN_C int _gl_cxxalias_dummy
142: #else
143: # define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \
144: _GL_EXTERN_C int _gl_cxxalias_dummy
145: #endif
146:
147: /* _GL_CXXALIAS_SYS (func, rettype, parameters);
148: declares a C++ alias called GNULIB_NAMESPACE::func
149: that redirects to the system provided function func, if GNULIB_NAMESPACE
150: is defined.
151: Example:
152: _GL_CXXALIAS_SYS (open, int, (const char *filename, int flags, ...));
153: */
154: #if defined __cplusplus && defined GNULIB_NAMESPACE
155: /* If we were to write
156: rettype (*const func) parameters = ::func;
157: like above in _GL_CXXALIAS_RPL_1, the compiler could optimize calls
158: better (remove an indirection through a 'static' pointer variable),
159: but then the _GL_CXXALIASWARN macro below would cause a warning not only
160: for uses of ::func but also for uses of GNULIB_NAMESPACE::func. */
161: # define _GL_CXXALIAS_SYS(func,rettype,parameters) \
162: namespace GNULIB_NAMESPACE \
163: { \
164: static rettype (*func) parameters = ::func; \
165: } \
166: _GL_EXTERN_C int _gl_cxxalias_dummy
167: #else
168: # define _GL_CXXALIAS_SYS(func,rettype,parameters) \
169: _GL_EXTERN_C int _gl_cxxalias_dummy
170: #endif
171:
172: /* _GL_CXXALIAS_SYS_CAST (func, rettype, parameters);
173: is like _GL_CXXALIAS_SYS (func, rettype, parameters);
174: except that the C function func may have a slightly different declaration.
175: A cast is used to silence the "invalid conversion" error that would
176: otherwise occur. */
177: #if defined __cplusplus && defined GNULIB_NAMESPACE
178: # define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
179: namespace GNULIB_NAMESPACE \
180: { \
181: static rettype (*func) parameters = \
182: reinterpret_cast<rettype(*)parameters>(::func); \
183: } \
184: _GL_EXTERN_C int _gl_cxxalias_dummy
185: #else
186: # define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
187: _GL_EXTERN_C int _gl_cxxalias_dummy
188: #endif
189:
190: /* _GL_CXXALIAS_SYS_CAST2 (func, rettype, parameters, rettype2, parameters2);
191: is like _GL_CXXALIAS_SYS (func, rettype, parameters);
192: except that the C function is picked among a set of overloaded functions,
193: namely the one with rettype2 and parameters2. Two consecutive casts
194: are used to silence the "cannot find a match" and "invalid conversion"
195: errors that would otherwise occur. */
196: #if defined __cplusplus && defined GNULIB_NAMESPACE
197: /* The outer cast must be a reinterpret_cast.
198: The inner cast: When the function is defined as a set of overloaded
199: functions, it works as a static_cast<>, choosing the designated variant.
200: When the function is defined as a single variant, it works as a
201: reinterpret_cast<>. The parenthesized cast syntax works both ways. */
202: # define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
203: namespace GNULIB_NAMESPACE \
204: { \
205: static rettype (*func) parameters = \
206: reinterpret_cast<rettype(*)parameters>( \
207: (rettype2(*)parameters2)(::func)); \
208: } \
209: _GL_EXTERN_C int _gl_cxxalias_dummy
210: #else
211: # define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
212: _GL_EXTERN_C int _gl_cxxalias_dummy
213: #endif
214:
215: /* _GL_CXXALIASWARN (func);
216: causes a warning to be emitted when ::func is used but not when
217: GNULIB_NAMESPACE::func is used. func must be defined without overloaded
218: variants. */
219: #if defined __cplusplus && defined GNULIB_NAMESPACE
220: # define _GL_CXXALIASWARN(func) \
221: _GL_CXXALIASWARN_1 (func, GNULIB_NAMESPACE)
222: # define _GL_CXXALIASWARN_1(func,namespace) \
223: _GL_CXXALIASWARN_2 (func, namespace)
224: /* To work around GCC bug <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
225: we enable the warning only when not optimizing. */
226: # if !__OPTIMIZE__
227: # define _GL_CXXALIASWARN_2(func,namespace) \
228: _GL_WARN_ON_USE (func, \
229: "The symbol ::" #func " refers to the system function. " \
230: "Use " #namespace "::" #func " instead.")
231: # elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
232: # define _GL_CXXALIASWARN_2(func,namespace) \
233: extern __typeof__ (func) func
234: # else
235: # define _GL_CXXALIASWARN_2(func,namespace) \
236: _GL_EXTERN_C int _gl_cxxalias_dummy
237: # endif
238: #else
239: # define _GL_CXXALIASWARN(func) \
240: _GL_EXTERN_C int _gl_cxxalias_dummy
241: #endif
242:
243: /* _GL_CXXALIASWARN1 (func, rettype, parameters_and_attributes);
244: causes a warning to be emitted when the given overloaded variant of ::func
245: is used but not when GNULIB_NAMESPACE::func is used. */
246: #if defined __cplusplus && defined GNULIB_NAMESPACE
247: # define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
248: _GL_CXXALIASWARN1_1 (func, rettype, parameters_and_attributes, \
249: GNULIB_NAMESPACE)
250: # define _GL_CXXALIASWARN1_1(func,rettype,parameters_and_attributes,namespace) \
251: _GL_CXXALIASWARN1_2 (func, rettype, parameters_and_attributes, namespace)
252: /* To work around GCC bug <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
253: we enable the warning only when not optimizing. */
254: # if !__OPTIMIZE__
255: # define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
256: _GL_WARN_ON_USE_CXX (func, rettype, parameters_and_attributes, \
257: "The symbol ::" #func " refers to the system function. " \
258: "Use " #namespace "::" #func " instead.")
259: # elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
260: # define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
261: extern __typeof__ (func) func
262: # else
263: # define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
264: _GL_EXTERN_C int _gl_cxxalias_dummy
265: # endif
266: #else
267: # define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
268: _GL_EXTERN_C int _gl_cxxalias_dummy
269: #endif
270:
271: #endif /* _GL_CXXDEFS_H */
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