REG_EPAREN Un-matched parenthesis group operators. REG_EBRACK Un-matched bracket list operators. REG_EBRACE Un-matched brace interval operators. REG_BADRPT Invalid use of repetition operators such as using '*' as the first character. REG_BADPAT Invalid use of pattern operators such as group or list. REG_BADBR Invalid use of back reference operator. The following errors can be returned by regcomp(): Regexec() returns zero for a successful match or REG_NOMATCH for failure.
#Linux regular expression not code
Regcomp() returns zero for a successful compilation or an error code for failure.
#Linux regular expression not free
POSIX pattern buffer freeing Supplying regfree() with a precompiled pattern buffer, preg will free the memory allocated to the pattern buffer by the compiling process, If bothĮrrbuf and errbuf_size are nonzero, errbuf is filled in with the first errbuf_size - 1 characters of the error message and a It returns the size of the errbuf required to contain the null-terminated error message string. Regerror() is passed the error code, errcode, the pattern buffer, preg, a pointer to a character string buffer, errbuf, and the POSIX error reporting regerror() is used to turn the error codes that can be returned by both regcomp() and regexec() into error message strings. Indicates the end offset of the match, which is the offset of the first character after the matching text. } regmatch_t Each rm_so element that is not -1 indicates the start offset of the next largest substring match within the string. The regmatch_t structure which is the type of pmatch is defined in. (Note that to return the offsets of N subexpression matches, nmatch must be at least N+1.) Any unused structure elements will contain the The entire regular expression's match addresses are stored in pmatch. Starting at the ith open parenthesis are stored in pmatch.
These are filled in by regexec() with substring match addresses. pmatch must beĭimensioned to have at least nmatch elements. REG_NOTEOL The match-end-of-line operator always fails to match (but see the compilation flag REG_NEWLINE above)īyte offsets Unless REG_NOSUB was set for the compilation of the pattern buffer, it is possible to obtain match addressing information. Portions of a string are passed to regexec() and the beginning of the string should not be interpreted as the beginning of the line. REG_NOTBOL The match-beginning-of-line operator always fails to match (but see the compilation flag REG_NEWLINE above) This flag may be used when different Which cause changes in matching behavior described below. eflags may be the bitwise- or of one or both of REG_NOTBOL and REG_NOTEOL Provide information regarding the location of any matches.
POSIX regex matching regexec() is used to match a null-terminated string against the precompiled pattern buffer, preg. Match-end-of-line operator ( $) matches the empty string immediately before a newline, regardless of whether eflags contains
Match-beginning-of-line operator ( ^) matches the empty string immediately after a newline, regardless of whether eflags, the execution flags REG_NEWLINE Match-any-character operators don't match a newline.Ī nonmatching list ( ) not containing a newline does not match a newline. The nmatch and pmatch arguments to regexec() are ignored if the pattern buffer supplied was compiled REG_NOSUB Do not report position of matches. Subsequent regexec() searches using this pattern buffer will be case insensitive. If not set, POSIX Basic Regular Expression syntax is REG_EXTENDED Use POSIX Extended Regular Expression syntax when interpreting regex. Regcomp() is supplied with preg, a pointer to a pattern buffer storage area regex, a pointer to the null-terminated string andĬflags, flags used to determine the type of compilation.Īll regular expression searching must be done via a compiled pattern buffer, thus regexec() must always be supplied with the address of aĬflags may be the bitwise- or of one or more of the following: POSIX regex compiling regcomp() is used to compile a regular expression into a form that is suitable for subsequent regexec() searches.