5 * (c) 2003 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of the mLib utilities library.
12 * mLib is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * mLib is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License along with mLib; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
35 /*----- Miscellaneous utility macros --------------------------------------*/
37 #define N(v) (sizeof(v)/sizeof(*v))
39 #define MLIB__STR(x) #x
40 #define STR(x) MLIB__STR(x)
42 #define MLIB__GLUE(x, y) x##y
43 #define GLUE(x, y) MLIB__GLUE(x, y)
45 /*----- Compiler diagnostics ----------------------------------------------*/
47 /* --- Compiler-specific definitions --- */
51 # define GCC_VERSION_P(maj, min) \
52 (__GNUC__ > (maj) || (__GNUC__ == (maj) && __GNUC_MINOR__ >= (min)))
54 # if GCC_VERSION_P(2, 5)
55 # define NORETURN __attribute__((noreturn))
56 # define PRINTF_LIKE(fix, aix) __attribute__((format(printf, fix, aix)))
57 # define SCANF_LIKE(fix, aix) __attribute__((format(scanf, fix, aix)))
58 # define IGNORABLE __attribute__((unused))
61 # if GCC_VERSION_P(4, 5)
62 # define DEPRECATED(msg) __attribute__((deprecated(msg)))
63 # elif GCC_VERSION_P(3, 1)
64 # define DEPRECATED(msg) __attribute__((deprecated))
67 # if GCC_VERSION_P(4, 0)
68 # define EXECL_LIKE(ntrail) __attribute__((sentinel(ntrail)))
71 # if GCC_VERSION_P(4, 6)
73 /* --- Diagnostic suppression in GCC: a tale of woe --- *
75 * This is extremely unpleasant, largely as a result of bugs in the GCC
76 * preprocessor's handling of @_Pragma@. The fundamental problem is
77 * that it's the preprocessor, and not the compiler proper, which
78 * detects @_Pragma@, emitting @#pragma@ lines into its output; and it
79 * does it during macro expansion, even if the macro is being expanded
80 * during argument collection. Since arguments are expanded before
81 * replacing the macro's invocation with its body, a pragma in an
82 * argument will be emitted %%\emph{before}%% any pragmata in the body,
83 * even if they appear before the argument in the body -- and even if
84 * the argument doesn't actually appear anywhere at all in the body.
86 * Another, rather less significant, problem is that @_Pragma@'s
87 * argument is a single string literal, recognized in translation phase
88 * 4, before string-literal concatenation in phase 6, so we must build
89 * pragma bodies as token lists and then stringify them.
91 * As a result, we need some subterfuge here. The @MLIB__PRAGMA_HACK@
92 * macro issues a @_Pragma@ on its argument token list, which it
93 * stringifies; this deals with the second problem. The first is
94 * trickier: we must delay expansion of @MLIB__PRAGMA_HACK@ from the
95 * argument collection phase to the body rescanning phase, and we do
96 * this by splitting the invocations between @GCC_WARNING@ macro calls:
97 * the name is left hanging from the previous call (or from
98 * @MLIB__MUFFLE_WARNINGS@, in the first case) and the body is supplied
99 * by @GCC_WARNING@, which also supplies the next @MLIB__PRAGMA_HACK@.
100 * The remaining problem is to make sure we can dispose of the final
101 * trailing @MLIB__PRAGMA_HACK@ harmlessly, which we do by introducing
102 * an extra argument @emitp@, which may be either @t@ or @nil@; this
103 * dispatches to an appropriate helper macro by means of token-pasting.
108 # define MLIB__PRAGMA_HACK_t(x) _Pragma(#x)
109 # define MLIB__PRAGMA_HACK_nil(x)
110 # define MLIB__PRAGMA_HACK(emitp, x) MLIB__PRAGMA_HACK_##emitp(x)
111 # define MLIB__MUFFLE_WARNINGS(warns, body) \
112 _Pragma("GCC diagnostic push") MLIB__PRAGMA_HACK \
116 _Pragma("GCC diagnostic pop")
117 # define GCC_WARNING(warn) \
118 (t, GCC diagnostic ignored warn) MLIB__PRAGMA_HACK
119 # define MUFFLE_WARNINGS_DECL(warns, body) \
120 MLIB__MUFFLE_WARNINGS(warns, body)
121 # define MUFFLE_WARNINGS_EXPR(warns, body) \
122 __extension__ ({ MLIB__MUFFLE_WARNINGS(warns, (body);) })
123 # define MUFFLE_WARNINGS_STMT(warns, body) \
124 do { MLIB__MUFFLE_WARNINGS(warns, body) } while (0)
129 /* --- Fallback definitions, mostly trivial --- */
131 #ifndef GCC_VERSION_P
132 # define GCC_VERSION_P(maj, min) 0
136 # define DEPRECATED(msg)
140 # define EXECL_LIKE(ntrail)
144 # define DISCARD(x) do if (x); while (0)
148 # define IGNORE(x) ((void)(x))
151 #ifndef MUFFLE_WARNINGS_DECL
152 # define MUFFLE_WARNINGS_DECL(warns, body) body
155 #ifndef MUFFLE_WARNINGS_EXPR
156 # define MUFFLE_WARNINGS_EXPR(warns, body) (body)
159 #ifndef MUFFLE_WARNINGS_STMT
160 # define MUFFLE_WARNINGS_STMT(warns, body) do { body } while (0)
164 # define PRINF_LIKE(fmtix, argix)
168 # define SCANF_LIKE(fmtix, argix)
176 # define GCC_WARNING(warn)
179 /*----- That's all, folks -------------------------------------------------*/