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14d7100d | 1 | .\" -*-nroff-*- |
c4ccbbf9 MW |
2 | .\" |
3 | .\" Manual for miscellaneous macros | |
4 | .\" | |
5 | .\" (c) 2003, 2005, 2009, 2013, 2018, 2019, 2022, 2024 Straylight/Edgeware | |
6 | .\" | |
7 | . | |
8 | .\"----- Licensing notice --------------------------------------------------- | |
9 | .\" | |
10 | .\" This file is part of the mLib utilities library. | |
11 | .\" | |
12 | .\" mLib is free software: you can redistribute it and/or modify it under | |
13 | .\" the terms of the GNU Library General Public License as published by | |
14 | .\" the Free Software Foundation; either version 2 of the License, or (at | |
15 | .\" your option) any later version. | |
16 | .\" | |
17 | .\" mLib is distributed in the hope that it will be useful, but WITHOUT | |
18 | .\" ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
19 | .\" FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public | |
20 | .\" License for more details. | |
21 | .\" | |
22 | .\" You should have received a copy of the GNU Library General Public | |
23 | .\" License along with mLib. If not, write to the Free Software | |
24 | .\" Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, | |
25 | .\" USA. | |
26 | . | |
27 | .\"-------------------------------------------------------------------------- | |
28 | .so ../defs.man \" @@@PRE@@@ | |
29 | . | |
30 | .\"-------------------------------------------------------------------------- | |
31 | .TH macros 3mLib "13 December 2003" "Straylight/Edgeware" "mLib utilities library" | |
14d7100d | 32 | .\" @N |
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33 | .\" @STR |
34 | .\" @GLUE | |
f50c1365 | 35 | .\" @STATIC_ASSERT |
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36 | .\" @ISALNUM |
37 | .\" @ISALPHA | |
38 | .\" @ISASCII | |
39 | .\" @ISBLANK | |
40 | .\" @ISCNTRL | |
41 | .\" @ISDIGIT | |
42 | .\" @ISGRAPH | |
43 | .\" @ISLOWER | |
44 | .\" @ISPRINT | |
45 | .\" @ISPUNCT | |
46 | .\" @ISSPACE | |
47 | .\" @ISUPPER | |
48 | .\" @ISXDIGIT | |
49 | .\" @TOASCII | |
50 | .\" @TOLOWER | |
51 | .\" @TOUPPER | |
52 | .\" @MEMCMP | |
53 | .\" @STRCMP | |
54 | .\" @STRNCMP | |
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55 | .\" @DISCARD |
56 | .\" @IGNORE | |
57 | .\" @DEPRECATED | |
58 | .\" @EXECL_LIKE | |
59 | .\" @IGNORABLE | |
8c470f2a | 60 | .\" @MUST_CHECK |
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61 | .\" @NORETURN |
62 | .\" @PRINTF_LIKE | |
63 | .\" @SCANF_LIKE | |
64 | .\" @MUFFLE_WARNINGS_DECL | |
65 | .\" @MUFFLE_WARNINGS_EXPR | |
66 | .\" @MUFFLE_WARNINGS_STMT | |
3832000d | 67 | .\" @GCC_WARNING |
2f2cb664 | 68 | .\" @CLANG_WARNING |
c4ccbbf9 MW |
69 | . |
70 | .\"-------------------------------------------------------------------------- | |
71 | .SH NAME | |
72 | macros \- useful macros | |
73 | . | |
74 | .\"-------------------------------------------------------------------------- | |
14d7100d | 75 | .SH SYNOPSIS |
c4ccbbf9 | 76 | . |
14d7100d | 77 | .nf |
78 | .B "#include <mLib/macros.h>" | |
d056fbdf | 79 | .PP |
14d7100d | 80 | .BI "size_t N(" array ");" |
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81 | .BI "STR(" tokens\fR... ")" |
82 | .BI "GLUE(" tokens\fR... ", " tokens\fR... ")" | |
f50c1365 | 83 | .BI "STATIC_ASSERT(" cond ", " msg ");" |
d056fbdf | 84 | .PP |
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85 | .BI "ISALNUM(int " ch ");" |
86 | .BI "ISALPHA(int " ch ");" | |
87 | .BI "ISASCII(int " ch ");" | |
88 | .BI "ISBLANK(int " ch ");" | |
89 | .BI "ISCNTRL(int " ch ");" | |
90 | .BI "ISDIGIT(int " ch ");" | |
91 | .BI "ISGRAPH(int " ch ");" | |
92 | .BI "ISLOWER(int " ch ");" | |
93 | .BI "ISPRINT(int " ch ");" | |
94 | .BI "ISPUNCT(int " ch ");" | |
95 | .BI "ISSPACE(int " ch ");" | |
96 | .BI "ISUPPER(int " ch ");" | |
97 | .BI "ISXDIGIT(int " ch ");" | |
98 | .BI "TOASCII(int " ch ");" | |
99 | .BI "TOLOWER(int " ch ");" | |
100 | .BI "TOUPPER(int " ch ");" | |
d056fbdf | 101 | .PP |
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102 | .BI "MEMCMP(const void *" x ", " op ", const void *" y ", size_t " n ");" |
103 | .BI "STRCMP(const char *" x ", " op ", const char *" y ");" | |
104 | .BI "STRNCMP(const char *" x ", " op ", const char *" y ", size_t " n ");" | |
d056fbdf | 105 | .PP |
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106 | .BI "void DISCARD(" scalar ");" |
107 | .BI "void IGNORE(" variable ");" | |
d056fbdf | 108 | .PP |
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109 | .BI "DEPRECATED(" msg ")" |
110 | .BI "EXECL_LIKE(" ntrail ")" | |
111 | .BI "IGNORABLE" | |
8c470f2a | 112 | .BI "MUST_CHECK" |
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113 | .BI "NORETURN" |
114 | .BI "PRINTF_LIKE(" fmt-index ", " arg-index ")" | |
115 | .BI "SCANF_LIKE(" fmt-index ", " arg-index ")" | |
d056fbdf | 116 | .PP |
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117 | .BI "MUFFLE_WARNINGS_DECL(" warns ", " decls ")" |
118 | .BI "MUFFLE_WARNINGS_EXPR(" warns ", " expr ")" | |
119 | .BI "MUFFLE_WARNINGS_STMT(" warns ", " stmt ")" | |
d056fbdf | 120 | .PP |
3832000d | 121 | .BI "GCC_WARNING(" option ")" |
c418910f | 122 | .BI "CLANG_WARNING(" option ")" |
14d7100d | 123 | .fi |
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124 | . |
125 | .\"-------------------------------------------------------------------------- | |
14d7100d | 126 | .SH DESCRIPTION |
c4ccbbf9 | 127 | . |
3832000d | 128 | .SS Utilities |
14d7100d | 129 | The |
130 | .B N | |
131 | macro returns the number of elements in the named | |
132 | .IR array . | |
3832000d MW |
133 | .PP |
134 | The | |
135 | .B STR | |
136 | macro expands to a string literal containing the result of expanding its | |
137 | argument | |
138 | .IR tokens . | |
139 | .PP | |
140 | The | |
141 | .B GLUE | |
142 | macro expands to a single token, which is the result of gluing together | |
143 | the tokens resulting from expanding its argument token lists. Each of | |
144 | the argument token lists must expand to a single preprocessing token, | |
145 | and the result of gluing these tokens together must be valid | |
146 | preprocessing token. | |
147 | .PP | |
148 | The | |
f50c1365 MW |
149 | .B STATIC_ASSERT |
150 | causes compilation to fail if the integer constant expression | |
151 | .I cond | |
152 | evaluates to zero. This macro uses the C11 | |
153 | .B static_assert | |
154 | declaration if available, and the | |
155 | .I msg | |
156 | will be reported in the compiler's diagnostic messsage; otherwise, the macro | |
157 | falls back to a somewhat ugly hack which currently ignores the | |
158 | .IR msg . | |
159 | .PP | |
160 | The | |
36188114 MW |
161 | .BR IS ...\& |
162 | and | |
163 | .BR TO ...\& | |
164 | macros are wrappers around the corresponding standard | |
165 | .B <ctype.h> | |
166 | macros with the corresponding lowercase names. They take care of | |
167 | forcing the character argument | |
168 | .I ch | |
169 | to | |
170 | .BR "unsigned char" : | |
171 | this conversion is necessary on platforms with signed | |
172 | .B char | |
173 | to avoid passing negative values into the standard macros. | |
174 | .PP | |
175 | The | |
176 | .BR MEMCMP , | |
177 | .BR STRCMP , | |
178 | and | |
179 | .B STRNCMP | |
180 | macros are wrappers around the standard | |
181 | .B <string.h> | |
182 | functions with the corresponding lowercase names. They take an | |
183 | additional argument | |
184 | .I op | |
185 | which is a equality or ordering operator (e.g., | |
186 | .B == | |
187 | or | |
188 | .BR > ) | |
189 | inserted between the two operands. The standard functions return a | |
190 | false value if and only if the operands are equal, which is | |
191 | counterintuitive and leads to mistakes; requiring an explicit relational | |
192 | operator should reduce the number of such mistakes. | |
193 | .PP | |
194 | The | |
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195 | .B DISCARD |
196 | macro discards its argument, which must be of some scalar type. This | |
197 | can be useful in muffling warnings about ignoring return codes in cases | |
198 | where you really don't care. | |
199 | .PP | |
200 | The | |
201 | .B IGNORE | |
202 | macro ignores its argument, which may be an expression of any type. | |
203 | This can be useful in muffling warnings about unused variables. | |
c4ccbbf9 | 204 | . |
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205 | .SS Annotations |
206 | The following annotations can be attached to function declarations and | |
207 | definitions, as part of the declaration specifiers. (Other positions | |
208 | may also work, depending on your compiler, but don't bet on it.) They | |
209 | might not have any effect, depending on your specific compiler. | |
210 | Currently only GCC is well supported, but exactly which features are | |
211 | available depend on the compiler version. | |
212 | .PP | |
213 | Using a function or variable marked as | |
214 | .B DEPRECATED | |
215 | may provoke a compiler warning; this warning may (depending on your | |
216 | compiler version) include the given | |
217 | .IR msg . | |
218 | .PP | |
219 | A variadic function marked as | |
220 | .B EXECL_LIKE | |
221 | must be called with a null pointer (i.e., an integer constant | |
222 | expression with value 0, cast to | |
223 | .BR "void *") | |
224 | in the variadic part of its argument list, followed by | |
225 | .I ntrail | |
226 | further arguments. Typically, | |
227 | .I ntrail | |
228 | is zero. Compilers may warn about misuse of such functions. | |
229 | .PP | |
230 | A function or variable marked as | |
231 | .B IGNORABLE | |
232 | need not be used. This may muffle warnings about leaving the marked | |
233 | definition unused. | |
234 | .PP | |
235 | A function marked as | |
8c470f2a MW |
236 | .B MUST_CHECK |
237 | returns an important value: a warning may be issued if a caller | |
238 | ignores the value. The return type must not be | |
239 | .BR void . | |
240 | .PP | |
241 | A function marked as | |
3832000d MW |
242 | .B NORETURN |
243 | must not return. It must have return type | |
244 | .BR void . | |
245 | This may be useful in muffling warnings about uninitialized variables, | |
246 | for example. | |
247 | .PP | |
248 | A variadic function marked as | |
249 | .B PRINTF_LIKE | |
250 | takes a | |
251 | .BR printf (3)-style | |
252 | format argument (in position | |
253 | .IR fmt-index , | |
254 | counting from 1) and a variable-length list of arguments to be formatted | |
255 | (starting from position | |
256 | .IR arg-index ). | |
257 | Compilers may warn about misuse of such functions. | |
258 | .PP | |
259 | A variadic function marked as | |
260 | .B SCANF_LIKE | |
261 | takes a | |
262 | .BR scanf (3)-style | |
263 | format argument (in position | |
264 | .IR fmt-index , | |
265 | counting from 1) and a variable-length list of arguments to be formatted | |
266 | (starting from position | |
267 | .IR arg-index ). | |
268 | Compilers may warn about misuse of such functions. | |
c4ccbbf9 | 269 | . |
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270 | .SS Muffling warnings |
271 | Some compilers allow you to muffle warnings in particular pieces of | |
272 | code. These macros provide a compiler-neutral interface to such | |
273 | facilities. Each macro takes an argument | |
274 | .IR warns , | |
275 | which is a sequence of calls to | |
276 | .IB compiler _WARNING | |
277 | macros listing the warnings to be muffled. The list may contain | |
278 | warnings for several different compilers. The other argument is a | |
279 | .I body | |
280 | consisting of declarations (in the case of | |
281 | .BR MUFFLE_WARNINGS_DECL ), | |
282 | an expression (for | |
283 | .BR MUFFLE_WARNINGS_EXPR ), | |
284 | or a statement (for | |
285 | .BR MUFFLE_WARNINGS_STMT ). | |
c4ccbbf9 | 286 | . |
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287 | .SS GCC-specific features |
288 | The | |
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289 | .B GCC_WARNING |
290 | macro is intended to be used in | |
291 | .I warns | |
292 | lists (see above). It takes a string-literal argument | |
293 | .I option | |
294 | naming a GCC warning option, e.g., | |
295 | .BR """\-Wdiv-by-zero""" . | |
c418910f MW |
296 | .PP |
297 | The | |
298 | .B CLANG_WARNING | |
299 | is similar, except that it works with the Clang compiler. | |
33e3ac90 MW |
300 | .PP |
301 | Note that including | |
302 | .B <mLib/macros.h> | |
303 | also defines the compiler-test macros in | |
304 | .BR <mLib/compiler.h>; | |
305 | see | |
306 | .BR compiler (3). | |
c4ccbbf9 MW |
307 | . |
308 | .\"-------------------------------------------------------------------------- | |
14d7100d | 309 | .SH "SEE ALSO" |
c4ccbbf9 | 310 | . |
33e3ac90 | 311 | .BR compiler (3). |
c4ccbbf9 MW |
312 | .BR mLib (3), |
313 | . | |
314 | .\"-------------------------------------------------------------------------- | |
14d7100d | 315 | .SH "AUTHOR" |
c4ccbbf9 | 316 | . |
9b5ac6ff | 317 | Mark Wooding, <mdw@distorted.org.uk> |
c4ccbbf9 MW |
318 | . |
319 | .\"----- That's all, folks -------------------------------------------------- |