[7aa7b7]: regex.3  Maximize  Restore  History

Download this file

303 lines (290 with data), 7.5 kB

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
.\" Copyright (C), 1995, Graeme W. Wilford. (Wilf.)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date. The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein. The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" Wed Jun 14 16:10:28 BST 1995 Wilf. (G.Wilford@ee.surrey.ac.uk)
.\" Tiny change in formatting - aeb, 950812
.\" Modified 8 May 1998 by Joseph S. Myers (jsm28@cam.ac.uk)
.\" 2007-04-30 Keith Marshall (keithmarshall@users.sourceforge.net)
.\" Adapt TH for inclusion in MinGW distribution kit
.\"
.\" show the synopsis section nicely
.de xx
.in \\n(INu+\\$1
.ti -\\$1
..
.TH REGEX 3 2007-04-30 MinGW "MinGW Programmer's Manual"
.SH NAME
regcomp, regexec, regerror, regfree \- POSIX regex functions
.SH SYNOPSIS
.B #include <sys/types.h>
.br
.B #include <regex.h>
.sp
.xx \w'\fBint\ regcomp(\fR'u
.BI "int\ regcomp(regex_t *" preg ", const char *" regex ,
.BI "int " cflags );
.xx \w'\fBint\ regexec(\fR'u
.BI "int\ regexec(const regex_t *" preg ", const char *" string ,
.BI "size_t " nmatch ", regmatch_t " pmatch[] ,
.BI "int " eflags );
.xx \w'\fBsize_t\ regerror(\fR'u
.BI "size_t\ regerror(int " errcode ,
.BI "const regex_t *" preg ", char *" errbuf ,
.BI "size_t " errbuf_size );
.xx \w'\fBvoid\ regfree(\fR'
.BI "void\ regfree(regex_t *" preg );
.SH "POSIX REGEX COMPILING"
.BR regcomp ()
is used to compile a regular expression into a form that is suitable
for subsequent
.BR regexec ()
searches.
.BR regcomp ()
is supplied with
.IR preg ,
a pointer to a pattern buffer storage area;
.IR regex ,
a pointer to the null-terminated string and
.IR cflags ,
flags used to determine the type of compilation.
All regular expression searching must be done via a compiled pattern
buffer, thus
.BR regexec ()
must always be supplied with the address of a
.BR regcomp ()
initialized pattern buffer.
.I cflags
may be the
.RB bitwise- or
of one or more of the following:
.TP
.B REG_EXTENDED
Use
.B POSIX
Extended Regular Expression syntax when interpreting
.IR regex .
If not set,
.B POSIX
Basic Regular Expression syntax is used.
.TP
.B REG_ICASE
Do not differentiate case. Subsequent
.BR regexec ()
searches using this pattern buffer will be case insensitive.
.TP
.B REG_NOSUB
Support for substring addressing of matches is not required.
The
.I nmatch
and
.I pmatch
parameters to
.BR regexec ()
are ignored if the pattern buffer supplied was compiled with this flag set.
.TP
.B REG_NEWLINE
Match-any-character operators don't match a newline.
A non-matching list
.RB ( [^...] )
not containing a newline does not match a newline.
Match-beginning-of-line operator
.RB ( ^ )
matches the empty string immediately after a newline, regardless of
whether
.IR eflags ,
the execution flags of
.BR regexec (),
contains
.BR REG_NOTBOL .
Match-end-of-line operator
.RB ( $ )
matches the empty string immediately before a newline, regardless of
whether
.IR eflags
contains
.BR REG_NOTEOL .
.SH "POSIX REGEX MATCHING"
.BR regexec ()
is used to match a null-terminated string
against the precompiled pattern buffer,
.IR preg .
.I nmatch
and
.I pmatch
are used to provide information regarding the location of any matches.
.I eflags
may be the
.RB bitwise- or
of one or both of
.B REG_NOTBOL
and
.B REG_NOTEOL
which cause changes in matching behaviour described below.
.TP
.B REG_NOTBOL
The match-beginning-of-line operator always fails to match (but see the
compilation flag
.B REG_NEWLINE
above)
This flag may be used when different portions of a string are passed to
.BR regexec ()
and the beginning of the string should not be interpreted as the
beginning of the line.
.TP
.B REG_NOTEOL
The match-end-of-line operator always fails to match (but see the
compilation flag
.B REG_NEWLINE
above)
.SS "BYTE OFFSETS"
Unless
.B REG_NOSUB
was set for the compilation of the pattern buffer, it is possible to
obtain substring match addressing information.
.I pmatch
must be dimensioned to have at least
.I nmatch
elements.
These are filled in by
.BR regexec ()
with substring match addresses. Any unused structure elements
will contain the value \-1.
The
.B regmatch_t
structure which is the type of
.I pmatch
is defined in
.IR regex.h .
.RS
.B typedef struct
.br
.B {
.br
.BI " regoff_t " rm_so ;
.br
.BI " regoff_t " rm_eo ;
.br
.B }
.B regmatch_t;
.RE
Each
.I rm_so
element that is not \-1 indicates the start offset of the next largest
substring match within the string. The relative
.I rm_eo
element indicates the end offset of the match.
.SH "POSIX ERROR REPORTING"
.BR regerror ()
is used to turn the error codes that can be returned by both
.BR regcomp ()
and
.BR regexec ()
into error message strings.
.BR regerror ()
is passed the error code,
.IR errcode ,
the pattern buffer,
.IR preg ,
a pointer to a character string buffer,
.IR errbuf ,
and the size of the string buffer,
.IR errbuf_size .
It returns the size of the
.I errbuf
required to contain the null-terminated error message string. If both
.I errbuf
and
.I errbuf_size
are non-zero,
.I errbuf
is filled in with the first
.I "errbuf_size \- 1"
characters of the error message and a terminating null.
.SH "POSIX PATTERN BUFFER FREEING"
Supplying
.BR regfree ()
with a precompiled pattern buffer,
.I preg
will free the memory allocated to the pattern buffer by the compiling
process,
.BR regcomp ().
.SH "RETURN VALUE"
.BR regcomp ()
returns zero for a successful compilation or an error code for failure.
.BR regexec ()
returns zero for a successful match or
.B REG_NOMATCH
for failure.
.SH ERRORS
The following errors can be returned by
.BR regcomp ():
.TP
.B REG_BADBR
Invalid use of back reference operator.
.TP
.B REG_BADPAT
Invalid use of pattern operators such as group or list.
.TP
.B REG_BADRPT
Invalid use of repetition operators such as using
.RB ` * '
as the first character.
.TP
.B REG_EBRACE
Un-matched brace interval operators.
.TP
.B REG_EBRACK
Un-matched bracket list operators.
.TP
.B REG_ECOLLATE
Invalid collating element.
.TP
.B REG_ECTYPE
Unknown character class name.
.TP
.B REG_EEND
Non specific error. This is not defined by POSIX.2.
.TP
.B REG_EESCAPE
Trailing backslash.
.TP
.B REG_EPAREN
Un-matched parenthesis group operators.
.TP
.B REG_ERANGE
Invalid use of the range operator, eg. the ending point of the range
occurs prior to the starting point.
.TP
.B REG_ESIZE
Compiled regular expression requires a pattern buffer larger than 64Kb.
This is not defined by POSIX.2.
.TP
.B REG_ESPACE
The regex routines ran out of memory.
.TP
.B REG_ESUBREG
Invalid back reference to a subexpression.
.SH "CONFORMING TO"
POSIX.2
.SH "SEE ALSO"
.BR regex (7),
GNU regex manual

Get latest updates about Open Source Projects, Conferences and News.

Sign up for the SourceForge newsletter:





No, thanks