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regex (3)
  • regex (1) ( Solaris man: Команды и прикладные программы пользовательского уровня )
  • regex (3) ( FreeBSD man: Библиотечные вызовы )
  • regex (3) ( Русские man: Библиотечные вызовы )
  • >> regex (3) ( Linux man: Библиотечные вызовы )
  • regex (5) ( Solaris man: Форматы файлов )
  • regex (7) ( Русские man: Макропакеты и соглашения )
  • regex (7) ( Linux man: Макропакеты и соглашения )
  • Ключ regex обнаружен в базе ключевых слов.
  •  

    NAME

    regcomp, regexec, regerror, regfree - POSIX regex functions
     
    

    SYNOPSIS

    #include <sys/types.h>
    #include <regex.h>
    
    int regcomp(regex_t *preg, const char *regex, int cflags);
    
    int regexec(const regex_t *preg, const char *string, size_t nmatch,
                regmatch_t pmatch[], int eflags);
    
    size_t regerror(int errcode, const regex_t *preg, char *errbuf,
                    size_t errbuf_size);
    
    void regfree(regex_t *preg);
    
     

    DESCRIPTION

     

    POSIX Regex Compiling

    regcomp() is used to compile a regular expression into a form that is suitable for subsequent regexec() searches.

    regcomp() is supplied with preg, a pointer to a pattern buffer storage area; regex, a pointer to the null-terminated string and cflags, flags used to determine the type of compilation.

    All regular expression searching must be done via a compiled pattern buffer, thus regexec() must always be supplied with the address of a regcomp() initialized pattern buffer.

    cflags may be the bitwise-or of one or more of the following:

    REG_EXTENDED
    Use POSIX Extended Regular Expression syntax when interpreting regex. If not set, POSIX Basic Regular Expression syntax is used.
    REG_ICASE
    Do not differentiate case. Subsequent regexec() searches using this pattern buffer will be case insensitive.
    REG_NOSUB
    Support for substring addressing of matches is not required. The nmatch and pmatch arguments to regexec() are ignored if the pattern buffer supplied was compiled with this flag set.
    REG_NEWLINE
    Match-any-character operators don't match a newline.

    A non-matching list ([^...]) not containing a newline does not match a newline.

    Match-beginning-of-line operator (^) matches the empty string immediately after a newline, regardless of whether eflags, the execution flags of regexec(), contains REG_NOTBOL.

    Match-end-of-line operator ($) matches the empty string immediately before a newline, regardless of whether eflags contains REG_NOTEOL.

     

    POSIX Regex Matching

    regexec() is used to match a null-terminated string against the precompiled pattern buffer, preg. nmatch and pmatch are used to provide information regarding the location of any matches. eflags may be the bitwise-or of one or both of REG_NOTBOL and REG_NOTEOL which cause changes in matching behavior described below.
    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 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_NOTEOL
    The match-end-of-line operator always fails to match (but see the compilation flag REG_NEWLINE above)
     

    Byte Offsets

    Unless REG_NOSUB was set for the compilation of the pattern buffer, it is possible to obtain substring match addressing information. pmatch must be dimensioned to have at least nmatch elements. These are filled in by regexec() with substring match addresses. Any unused structure elements will contain the value -1.

    The regmatch_t structure which is the type of pmatch is defined in <regex.h>.

    typedef struct {
        regoff_t rm_so;
        regoff_t rm_eo;
    } regmatch_t;
    

    Each rm_so element that is not -1 indicates the start offset of the next largest substring match within the string. The relative rm_eo element indicates the end offset of the match, which is the offset of the first character after the matching text.  

    Posix Error Reporting

    regerror() is used to turn the error codes that can be returned by both regcomp() and regexec() into error message strings.

    regerror() is passed the error code, errcode, the pattern buffer, preg, a pointer to a character string buffer, errbuf, and the size of the string buffer, errbuf_size. It returns the size of the errbuf required to contain the null-terminated error message string. If both errbuf and errbuf_size are non-zero, errbuf is filled in with the first errbuf_size - 1 characters of the error message and a terminating null.  

    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, regcomp().  

    RETURN VALUE

    regcomp() returns zero for a successful compilation or an error code for failure.

    regexec() returns zero for a successful match or REG_NOMATCH for failure.  

    ERRORS

    The following errors can be returned by regcomp():
    REG_BADBR
    Invalid use of back reference operator.
    REG_BADPAT
    Invalid use of pattern operators such as group or list.
    REG_BADRPT
    Invalid use of repetition operators such as using aq*aq as the first character.
    REG_EBRACE
    Un-matched brace interval operators.
    REG_EBRACK
    Un-matched bracket list operators.
    REG_ECOLLATE
    Invalid collating element.
    REG_ECTYPE
    Unknown character class name.
    REG_EEND
    Non specific error. This is not defined by POSIX.2.
    REG_EESCAPE
    Trailing backslash.
    REG_EPAREN
    Un-matched parenthesis group operators.
    REG_ERANGE
    Invalid use of the range operator, e.g., the ending point of the range occurs prior to the starting point.
    REG_ESIZE
    Compiled regular expression requires a pattern buffer larger than 64Kb. This is not defined by POSIX.2.
    REG_ESPACE
    The regex routines ran out of memory.
    REG_ESUBREG
    Invalid back reference to a subexpression.
     

    CONFORMING TO

    POSIX.1-2001.  

    SEE ALSO

    grep(1), regex(7), GNU regex manual  

    COLOPHON

    This page is part of release 3.14 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


     

    Index

    NAME
    SYNOPSIS
    DESCRIPTION
    POSIX Regex Compiling
    POSIX Regex Matching
    Byte Offsets
    Posix Error Reporting
    POSIX Pattern Buffer Freeing
    RETURN VALUE
    ERRORS
    CONFORMING TO
    SEE ALSO
    COLOPHON


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