1 <!-- ##### SECTION Title ##### -->
2 Perl-compatible regular expressions
4 <!-- ##### SECTION Short_Description ##### -->
5 matches strings against regular expressions.
7 <!-- ##### SECTION Long_Description ##### -->
9 The <function>g_regex_*()</function> functions implement regular
10 expression pattern matching using syntax and semantics similar to
11 Perl regular expression.
14 Some functions accept a <parameter>start_position</parameter> argument,
15 setting it differs from just passing over a shortened string and setting
16 #G_REGEX_MATCH_NOTBOL in the case of a pattern that begins with any kind
17 of lookbehind assertion.
18 For example, consider the pattern "\Biss\B" which finds occurrences of "iss"
19 in the middle of words. ("\B" matches only if the current position in the
20 subject is not a word boundary.) When applied to the string "Mississipi"
21 from the fourth byte, namely "issipi", it does not match, because "\B" is
22 always false at the start of the subject, which is deemed to be a word
23 boundary. However, if the entire string is passed , but with
24 <parameter>start_position</parameter> set to 4, it finds the second
25 occurrence of "iss" because it is able to look behind the starting point
26 to discover that it is preceded by a letter.
29 Note that, unless you set the #G_REGEX_RAW flag, all the strings passed
30 to these functions must be encoded in UTF-8. The lengths and the positions
31 inside the strings are in bytes and not in characters, so, for instance,
32 "\xc3\xa0" (i.e. "à") is two bytes long but it is treated as a single
33 character. If you set #G_REGEX_RAW the strings can be non-valid UTF-8
34 strings and a byte is treated as a character, so "\xc3\xa0" is two bytes
35 and two characters long.
38 When matching a pattern, "\n" matches only against a "\n" character in the
39 string, and "\r" matches only a "\r" character. To match any newline sequence
40 use "\R". This particular group matches either the two-character sequence
41 CR + LF ("\r\n"), or one of the single characters LF (linefeed, U+000A, "\n"), VT
42 (vertical tab, U+000B, "\v"), FF (formfeed, U+000C, "\f"), CR (carriage return,
43 U+000D, "\r"), NEL (next line, U+0085), LS (line separator, U+2028), or PS
44 (paragraph separator, U+2029).
47 The behaviour of the dot, circumflex, and dollar metacharacters are affected by
48 newline characters, the default is to recognize any newline character (the same
49 characters recognized by "\R"). This can be changed with #G_REGEX_NEWLINE_CR,
50 #G_REGEX_NEWLINE_LF and #G_REGEX_NEWLINE_CRLF compile options,
51 and with #G_REGEX_MATCH_NEWLINE_ANY, #G_REGEX_MATCH_NEWLINE_CR,
52 #G_REGEX_MATCH_NEWLINE_LF and #G_REGEX_MATCH_NEWLINE_CRLF match options.
53 These settings are also relevant when compiling a pattern if
54 #G_REGEX_EXTENDED is set, and an unescaped "#" outside a character class is
55 encountered. This indicates a comment that lasts until after the next
59 If you have two threads manipulating the same #GRegex, they must use a
60 lock to synchronize their operation, as these functions are not threadsafe.
61 Creating and manipulating different #GRegex structures from different
62 threads is not a problem.
65 The regular expressions low level functionalities are obtained through
66 the excellent <ulink url="http://www.pcre.org/">PCRE</ulink> library
67 written by Philip Hazel.
70 <!-- ##### SECTION See_Also ##### -->
75 <!-- ##### SECTION Stability_Level ##### -->
78 <!-- ##### ENUM GRegexError ##### -->
80 Error codes returned by regular expressions functions.
83 @G_REGEX_ERROR_COMPILE: Compilation of the regular expression in <function>g_regex_new()</function> failed.
84 @G_REGEX_ERROR_OPTIMIZE: Optimization of the regular expression in <function>g_regex_optimize()</function> failed.
85 @G_REGEX_ERROR_REPLACE: Replacement failed due to an ill-formed replacement string.
86 @G_REGEX_ERROR_MATCH: The match process failed.
89 <!-- ##### MACRO G_REGEX_ERROR ##### -->
91 Error domain for regular expressions. Errors in this domain will be from the #GRegexError enumeration. See #GError for information on error domains.
97 <!-- ##### ENUM GRegexCompileFlags ##### -->
99 Flags specifying compile-time options.
102 @G_REGEX_CASELESS: Letters in the pattern match both upper and lower case
103 letters. It be changed within a pattern by a "(?i)" option setting.
104 @G_REGEX_MULTILINE: By default, GRegex treats the strings as consisting
105 of a single line of characters (even if it actually contains newlines).
106 The "start of line" metacharacter ("^") matches only at the start of the
107 string, while the "end of line" metacharacter ("$") matches only at the
108 end of the string, or before a terminating newline (unless
109 #G_REGEX_DOLLAR_ENDONLY is set). When #G_REGEX_MULTILINE is set,
110 the "start of line" and "end of line" constructs match immediately following
111 or immediately before any newline in the string, respectively, as well
112 as at the very start and end. This can be changed within a pattern by a
113 "(?m)" option setting.
114 @G_REGEX_DOTALL: A dot metacharater (".") in the pattern matches all
115 characters, including newlines. Without it, newlines are excluded. This
116 option can be changed within a pattern by a ("?s") option setting.
117 @G_REGEX_EXTENDED: Whitespace data characters in the pattern are
118 totally ignored except when escaped or inside a character class.
119 Whitespace does not include the VT character (code 11). In addition,
120 characters between an unescaped "#" outside a character class and
121 the next newline character, inclusive, are also ignored. This can be
122 changed within a pattern by a "(?x)" option setting.
123 @G_REGEX_ANCHORED: The pattern is forced to be "anchored", that is,
124 it is constrained to match only at the first matching point in the string
125 that is being searched. This effect can also be achieved by appropriate
126 constructs in the pattern itself such as the "^" metacharater.
127 @G_REGEX_DOLLAR_ENDONLY: A dollar metacharacter ("$") in the pattern
128 matches only at the end of the string. Without this option, a dollar also
129 matches immediately before the final character if it is a newline (but
130 not before any other newlines). This option is ignored if
131 #G_REGEX_MULTILINE is set.
132 @G_REGEX_UNGREEDY: Inverts the "greediness" of the
133 quantifiers so that they are not greedy by default, but become greedy
134 if followed by "?". It can also be set by a "(?U)" option setting within
136 @G_REGEX_RAW: Usually strings must be valid UTF-8 strings, using this
137 flag they are considered as a raw sequence of bytes.
138 @G_REGEX_NO_AUTO_CAPTURE: Disables the use of numbered capturing
139 parentheses in the pattern. Any opening parenthesis that is not followed
140 by "?" behaves as if it were followed by "?:" but named parentheses can
141 still be used for capturing (and they acquire numbers in the usual way).
142 @G_REGEX_DUPNAMES: Names used to identify capturing subpatterns need not
143 be unique. This can be helpful for certain types of pattern when it is known
144 that only one instance of the named subpattern can ever be matched.
145 @G_REGEX_NEWLINE_CR: Usually any newline character is recognized, if this
146 option is set, the only recognized newline character is '\r'.
147 @G_REGEX_NEWLINE_LF: Usually any newline character is recognized, if this
148 option is set, the only recognized newline character is '\n'.
149 @G_REGEX_NEWLINE_CRLF: Usually any newline character is recognized, if this
150 option is set, the only recognized newline character sequence is '\r\n'.
153 <!-- ##### ENUM GRegexMatchFlags ##### -->
155 Flags specifying match-time options.
158 @G_REGEX_MATCH_ANCHORED: The pattern is forced to be "anchored", that is,
159 it is constrained to match only at the first matching point in the string
160 that is being searched. This effect can also be achieved by appropriate
161 constructs in the pattern itself such as the "^" metacharater.
162 @G_REGEX_MATCH_NOTBOL: Specifies that first character of the string is
163 not the beginning of a line, so the circumflex metacharacter should not
164 match before it. Setting this without G_REGEX_MULTILINE (at compile time)
165 causes circumflex never to match. This option affects only the behaviour of
166 the circumflex metacharacter, it does not affect "\A".
167 @G_REGEX_MATCH_NOTEOL: Specifies that the end of the subject string is
168 not the end of a line, so the dollar metacharacter should not match it nor
169 (except in multiline mode) a newline immediately before it. Setting this
170 without G_REGEX_MULTILINE (at compile time) causes dollar never to match.
171 This option affects only the behaviour of the dollar metacharacter, it does
172 not affect "\Z" or "\z".
173 @G_REGEX_MATCH_NOTEMPTY: An empty string is not considered to be a valid
174 match if this option is set. If there are alternatives in the pattern, they
175 are tried. If all the alternatives match the empty string, the entire match
176 fails. For example, if the pattern "a?b?" is applied to a string not beginning
177 with "a" or "b", it matches the empty string at the start of the string.
178 With this flag set, this match is not valid, so GRegex searches further
179 into the string for occurrences of "a" or "b".
180 @G_REGEX_MATCH_PARTIAL: Turns on the partial matching feature, for more
181 documentation on partial matching see g_regex_is_partial_match().
182 @G_REGEX_MATCH_NEWLINE_CR: Overrides the newline definition set when creating
183 a new #GRegex, setting the '\r' character as line terminator.
184 @G_REGEX_MATCH_NEWLINE_LF: Overrides the newline definition set when creating
185 a new #GRegex, setting the '\n' character as line terminator.
186 @G_REGEX_MATCH_NEWLINE_CRLF: Overrides the newline definition set when creating
187 a new #GRegex, setting the '\r\n' characters as line terminator.
188 @G_REGEX_MATCH_NEWLINE_ANY: Overrides the newline definition set when creating
189 a new #GRegex, any newline character or character sequence is recognized.
192 <!-- ##### STRUCT GRegex ##### -->
194 A GRegex is the "compiled" form of a regular expression pattern. This
195 structure is opaque and its fields cannot be accessed directly.
200 <!-- ##### USER_FUNCTION GRegexEvalCallback ##### -->
202 Specifies the type of the function passed to g_regex_replace_eval().
203 It is called for each occurance of the pattern @regex in @string, and it
204 should append the replacement to @result.
208 Do not call on @regex functions that modify its internal state, such as
209 g_regex_match(); if you need it you can create a temporary copy of
210 @regex using g_regex_copy().
214 @Param2: the string used to perform matches against.
215 @Param3: a #GString containing the new string.
216 @Param4: user data passed to g_regex_replace_eval().
217 @Returns: %FALSE to continue the replacement process, %TRUE to stop it.
221 <!-- ##### FUNCTION g_regex_new ##### -->
233 <!-- ##### FUNCTION g_regex_free ##### -->
241 <!-- ##### FUNCTION g_regex_optimize ##### -->
251 <!-- ##### FUNCTION g_regex_copy ##### -->
260 <!-- ##### FUNCTION g_regex_get_pattern ##### -->
269 <!-- ##### FUNCTION g_regex_clear ##### -->
277 <!-- ##### FUNCTION g_regex_match_simple ##### -->
289 <!-- ##### FUNCTION g_regex_match ##### -->
300 <!-- ##### FUNCTION g_regex_match_full ##### -->
314 <!-- ##### FUNCTION g_regex_match_next ##### -->
325 <!-- ##### FUNCTION g_regex_match_next_full ##### -->
339 <!-- ##### FUNCTION g_regex_match_all ##### -->
350 <!-- ##### FUNCTION g_regex_match_all_full ##### -->
364 <!-- ##### FUNCTION g_regex_get_match_count ##### -->
373 <!-- ##### FUNCTION g_regex_is_partial_match ##### -->
382 <!-- ##### FUNCTION g_regex_fetch ##### -->
393 <!-- ##### FUNCTION g_regex_fetch_pos ##### -->
405 <!-- ##### FUNCTION g_regex_fetch_named ##### -->
416 <!-- ##### FUNCTION g_regex_fetch_named_pos ##### -->
428 <!-- ##### FUNCTION g_regex_fetch_all ##### -->
438 <!-- ##### FUNCTION g_regex_get_string_number ##### -->
448 <!-- ##### FUNCTION g_regex_split_simple ##### -->
460 <!-- ##### FUNCTION g_regex_split ##### -->
471 <!-- ##### FUNCTION g_regex_split_full ##### -->
486 <!-- ##### FUNCTION g_regex_split_next ##### -->
497 <!-- ##### FUNCTION g_regex_split_next_full ##### -->
511 <!-- ##### FUNCTION g_regex_expand_references ##### -->
523 <!-- ##### FUNCTION g_regex_replace ##### -->
538 <!-- ##### FUNCTION g_regex_replace_literal ##### -->
553 <!-- ##### FUNCTION g_regex_replace_eval ##### -->
569 <!-- ##### FUNCTION g_regex_escape_string ##### -->