Annotation of embedaddon/libiconv/srclib/c++defs.h, revision 1.1
1.1 ! misho 1: /* C++ compatible function declaration macros.
! 2: Copyright (C) 2010-2019 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 <https://www.gnu.org/licenses/>. */
! 16:
! 17: #ifndef _GL_CXXDEFS_H
! 18: #define _GL_CXXDEFS_H
! 19:
! 20: /* Begin/end the GNULIB_NAMESPACE namespace. */
! 21: #if defined __cplusplus && defined GNULIB_NAMESPACE
! 22: # define _GL_BEGIN_NAMESPACE namespace GNULIB_NAMESPACE {
! 23: # define _GL_END_NAMESPACE }
! 24: #else
! 25: # define _GL_BEGIN_NAMESPACE
! 26: # define _GL_END_NAMESPACE
! 27: #endif
! 28:
! 29: /* The three most frequent use cases of these macros are:
! 30:
! 31: * For providing a substitute for a function that is missing on some
! 32: platforms, but is declared and works fine on the platforms on which
! 33: it exists:
! 34:
! 35: #if @GNULIB_FOO@
! 36: # if !@HAVE_FOO@
! 37: _GL_FUNCDECL_SYS (foo, ...);
! 38: # endif
! 39: _GL_CXXALIAS_SYS (foo, ...);
! 40: _GL_CXXALIASWARN (foo);
! 41: #elif defined GNULIB_POSIXCHECK
! 42: ...
! 43: #endif
! 44:
! 45: * For providing a replacement for a function that exists on all platforms,
! 46: but is broken/insufficient and needs to be replaced on some platforms:
! 47:
! 48: #if @GNULIB_FOO@
! 49: # if @REPLACE_FOO@
! 50: # if !(defined __cplusplus && defined GNULIB_NAMESPACE)
! 51: # undef foo
! 52: # define foo rpl_foo
! 53: # endif
! 54: _GL_FUNCDECL_RPL (foo, ...);
! 55: _GL_CXXALIAS_RPL (foo, ...);
! 56: # else
! 57: _GL_CXXALIAS_SYS (foo, ...);
! 58: # endif
! 59: _GL_CXXALIASWARN (foo);
! 60: #elif defined GNULIB_POSIXCHECK
! 61: ...
! 62: #endif
! 63:
! 64: * For providing a replacement for a function that exists on some platforms
! 65: but is broken/insufficient and needs to be replaced on some of them and
! 66: is additionally either missing or undeclared on some other platforms:
! 67:
! 68: #if @GNULIB_FOO@
! 69: # if @REPLACE_FOO@
! 70: # if !(defined __cplusplus && defined GNULIB_NAMESPACE)
! 71: # undef foo
! 72: # define foo rpl_foo
! 73: # endif
! 74: _GL_FUNCDECL_RPL (foo, ...);
! 75: _GL_CXXALIAS_RPL (foo, ...);
! 76: # else
! 77: # if !@HAVE_FOO@ or if !@HAVE_DECL_FOO@
! 78: _GL_FUNCDECL_SYS (foo, ...);
! 79: # endif
! 80: _GL_CXXALIAS_SYS (foo, ...);
! 81: # endif
! 82: _GL_CXXALIASWARN (foo);
! 83: #elif defined GNULIB_POSIXCHECK
! 84: ...
! 85: #endif
! 86: */
! 87:
! 88: /* _GL_EXTERN_C declaration;
! 89: performs the declaration with C linkage. */
! 90: #if defined __cplusplus
! 91: # define _GL_EXTERN_C extern "C"
! 92: #else
! 93: # define _GL_EXTERN_C extern
! 94: #endif
! 95:
! 96: /* _GL_FUNCDECL_RPL (func, rettype, parameters_and_attributes);
! 97: declares a replacement function, named rpl_func, with the given prototype,
! 98: consisting of return type, parameters, and attributes.
! 99: Example:
! 100: _GL_FUNCDECL_RPL (open, int, (const char *filename, int flags, ...)
! 101: _GL_ARG_NONNULL ((1)));
! 102: */
! 103: #define _GL_FUNCDECL_RPL(func,rettype,parameters_and_attributes) \
! 104: _GL_FUNCDECL_RPL_1 (rpl_##func, rettype, parameters_and_attributes)
! 105: #define _GL_FUNCDECL_RPL_1(rpl_func,rettype,parameters_and_attributes) \
! 106: _GL_EXTERN_C rettype rpl_func parameters_and_attributes
! 107:
! 108: /* _GL_FUNCDECL_SYS (func, rettype, parameters_and_attributes);
! 109: declares the system function, named func, with the given prototype,
! 110: consisting of return type, parameters, and attributes.
! 111: Example:
! 112: _GL_FUNCDECL_SYS (open, int, (const char *filename, int flags, ...)
! 113: _GL_ARG_NONNULL ((1)));
! 114: */
! 115: #define _GL_FUNCDECL_SYS(func,rettype,parameters_and_attributes) \
! 116: _GL_EXTERN_C rettype func parameters_and_attributes
! 117:
! 118: /* _GL_CXXALIAS_RPL (func, rettype, parameters);
! 119: declares a C++ alias called GNULIB_NAMESPACE::func
! 120: that redirects to rpl_func, if GNULIB_NAMESPACE is defined.
! 121: Example:
! 122: _GL_CXXALIAS_RPL (open, int, (const char *filename, int flags, ...));
! 123:
! 124: Wrapping rpl_func in an object with an inline conversion operator
! 125: avoids a reference to rpl_func unless GNULIB_NAMESPACE::func is
! 126: actually used in the program. */
! 127: #define _GL_CXXALIAS_RPL(func,rettype,parameters) \
! 128: _GL_CXXALIAS_RPL_1 (func, rpl_##func, rettype, parameters)
! 129: #if defined __cplusplus && defined GNULIB_NAMESPACE
! 130: # define _GL_CXXALIAS_RPL_1(func,rpl_func,rettype,parameters) \
! 131: namespace GNULIB_NAMESPACE \
! 132: { \
! 133: static const struct _gl_ ## func ## _wrapper \
! 134: { \
! 135: typedef rettype (*type) parameters; \
! 136: \
! 137: inline operator type () const \
! 138: { \
! 139: return ::rpl_func; \
! 140: } \
! 141: } func = {}; \
! 142: } \
! 143: _GL_EXTERN_C int _gl_cxxalias_dummy
! 144: #else
! 145: # define _GL_CXXALIAS_RPL_1(func,rpl_func,rettype,parameters) \
! 146: _GL_EXTERN_C int _gl_cxxalias_dummy
! 147: #endif
! 148:
! 149: /* _GL_CXXALIAS_RPL_CAST_1 (func, rpl_func, rettype, parameters);
! 150: is like _GL_CXXALIAS_RPL_1 (func, rpl_func, rettype, parameters);
! 151: except that the C function rpl_func may have a slightly different
! 152: declaration. A cast is used to silence the "invalid conversion" error
! 153: that would otherwise occur. */
! 154: #if defined __cplusplus && defined GNULIB_NAMESPACE
! 155: # define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \
! 156: namespace GNULIB_NAMESPACE \
! 157: { \
! 158: static const struct _gl_ ## func ## _wrapper \
! 159: { \
! 160: typedef rettype (*type) parameters; \
! 161: \
! 162: inline operator type () const \
! 163: { \
! 164: return reinterpret_cast<type>(::rpl_func); \
! 165: } \
! 166: } func = {}; \
! 167: } \
! 168: _GL_EXTERN_C int _gl_cxxalias_dummy
! 169: #else
! 170: # define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \
! 171: _GL_EXTERN_C int _gl_cxxalias_dummy
! 172: #endif
! 173:
! 174: /* _GL_CXXALIAS_SYS (func, rettype, parameters);
! 175: declares a C++ alias called GNULIB_NAMESPACE::func
! 176: that redirects to the system provided function func, if GNULIB_NAMESPACE
! 177: is defined.
! 178: Example:
! 179: _GL_CXXALIAS_SYS (open, int, (const char *filename, int flags, ...));
! 180:
! 181: Wrapping func in an object with an inline conversion operator
! 182: avoids a reference to func unless GNULIB_NAMESPACE::func is
! 183: actually used in the program. */
! 184: #if defined __cplusplus && defined GNULIB_NAMESPACE
! 185: # define _GL_CXXALIAS_SYS(func,rettype,parameters) \
! 186: namespace GNULIB_NAMESPACE \
! 187: { \
! 188: static const struct _gl_ ## func ## _wrapper \
! 189: { \
! 190: typedef rettype (*type) parameters; \
! 191: \
! 192: inline operator type () const \
! 193: { \
! 194: return ::func; \
! 195: } \
! 196: } func = {}; \
! 197: } \
! 198: _GL_EXTERN_C int _gl_cxxalias_dummy
! 199: #else
! 200: # define _GL_CXXALIAS_SYS(func,rettype,parameters) \
! 201: _GL_EXTERN_C int _gl_cxxalias_dummy
! 202: #endif
! 203:
! 204: /* _GL_CXXALIAS_SYS_CAST (func, rettype, parameters);
! 205: is like _GL_CXXALIAS_SYS (func, rettype, parameters);
! 206: except that the C function func may have a slightly different declaration.
! 207: A cast is used to silence the "invalid conversion" error that would
! 208: otherwise occur. */
! 209: #if defined __cplusplus && defined GNULIB_NAMESPACE
! 210: # define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
! 211: namespace GNULIB_NAMESPACE \
! 212: { \
! 213: static const struct _gl_ ## func ## _wrapper \
! 214: { \
! 215: typedef rettype (*type) parameters; \
! 216: \
! 217: inline operator type () const \
! 218: { \
! 219: return reinterpret_cast<type>(::func); \
! 220: } \
! 221: } func = {}; \
! 222: } \
! 223: _GL_EXTERN_C int _gl_cxxalias_dummy
! 224: #else
! 225: # define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
! 226: _GL_EXTERN_C int _gl_cxxalias_dummy
! 227: #endif
! 228:
! 229: /* _GL_CXXALIAS_SYS_CAST2 (func, rettype, parameters, rettype2, parameters2);
! 230: is like _GL_CXXALIAS_SYS (func, rettype, parameters);
! 231: except that the C function is picked among a set of overloaded functions,
! 232: namely the one with rettype2 and parameters2. Two consecutive casts
! 233: are used to silence the "cannot find a match" and "invalid conversion"
! 234: errors that would otherwise occur. */
! 235: #if defined __cplusplus && defined GNULIB_NAMESPACE
! 236: /* The outer cast must be a reinterpret_cast.
! 237: The inner cast: When the function is defined as a set of overloaded
! 238: functions, it works as a static_cast<>, choosing the designated variant.
! 239: When the function is defined as a single variant, it works as a
! 240: reinterpret_cast<>. The parenthesized cast syntax works both ways. */
! 241: # define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
! 242: namespace GNULIB_NAMESPACE \
! 243: { \
! 244: static const struct _gl_ ## func ## _wrapper \
! 245: { \
! 246: typedef rettype (*type) parameters; \
! 247: \
! 248: inline operator type () const \
! 249: { \
! 250: return reinterpret_cast<type>((rettype2 (*) parameters2)(::func)); \
! 251: } \
! 252: } func = {}; \
! 253: } \
! 254: _GL_EXTERN_C int _gl_cxxalias_dummy
! 255: #else
! 256: # define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
! 257: _GL_EXTERN_C int _gl_cxxalias_dummy
! 258: #endif
! 259:
! 260: /* _GL_CXXALIASWARN (func);
! 261: causes a warning to be emitted when ::func is used but not when
! 262: GNULIB_NAMESPACE::func is used. func must be defined without overloaded
! 263: variants. */
! 264: #if defined __cplusplus && defined GNULIB_NAMESPACE
! 265: # define _GL_CXXALIASWARN(func) \
! 266: _GL_CXXALIASWARN_1 (func, GNULIB_NAMESPACE)
! 267: # define _GL_CXXALIASWARN_1(func,namespace) \
! 268: _GL_CXXALIASWARN_2 (func, namespace)
! 269: /* To work around GCC bug <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
! 270: we enable the warning only when not optimizing. */
! 271: # if !__OPTIMIZE__
! 272: # define _GL_CXXALIASWARN_2(func,namespace) \
! 273: _GL_WARN_ON_USE (func, \
! 274: "The symbol ::" #func " refers to the system function. " \
! 275: "Use " #namespace "::" #func " instead.")
! 276: # elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
! 277: # define _GL_CXXALIASWARN_2(func,namespace) \
! 278: extern __typeof__ (func) func
! 279: # else
! 280: # define _GL_CXXALIASWARN_2(func,namespace) \
! 281: _GL_EXTERN_C int _gl_cxxalias_dummy
! 282: # endif
! 283: #else
! 284: # define _GL_CXXALIASWARN(func) \
! 285: _GL_EXTERN_C int _gl_cxxalias_dummy
! 286: #endif
! 287:
! 288: /* _GL_CXXALIASWARN1 (func, rettype, parameters_and_attributes);
! 289: causes a warning to be emitted when the given overloaded variant of ::func
! 290: is used but not when GNULIB_NAMESPACE::func is used. */
! 291: #if defined __cplusplus && defined GNULIB_NAMESPACE
! 292: # define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
! 293: _GL_CXXALIASWARN1_1 (func, rettype, parameters_and_attributes, \
! 294: GNULIB_NAMESPACE)
! 295: # define _GL_CXXALIASWARN1_1(func,rettype,parameters_and_attributes,namespace) \
! 296: _GL_CXXALIASWARN1_2 (func, rettype, parameters_and_attributes, namespace)
! 297: /* To work around GCC bug <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
! 298: we enable the warning only when not optimizing. */
! 299: # if !__OPTIMIZE__
! 300: # define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
! 301: _GL_WARN_ON_USE_CXX (func, rettype, parameters_and_attributes, \
! 302: "The symbol ::" #func " refers to the system function. " \
! 303: "Use " #namespace "::" #func " instead.")
! 304: # elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
! 305: # define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
! 306: extern __typeof__ (func) func
! 307: # else
! 308: # define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
! 309: _GL_EXTERN_C int _gl_cxxalias_dummy
! 310: # endif
! 311: #else
! 312: # define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
! 313: _GL_EXTERN_C int _gl_cxxalias_dummy
! 314: #endif
! 315:
! 316: #endif /* _GL_CXXDEFS_H */
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