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Diffstat (limited to 'man/man3/regexp.3')
| -rw-r--r-- | man/man3/regexp.3 | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/man/man3/regexp.3 b/man/man3/regexp.3 new file mode 100644 index 00000000..13c974c3 --- /dev/null +++ b/man/man3/regexp.3 @@ -0,0 +1,212 @@ +.TH REGEXP 3 +.SH NAME +regcomp, regcomplit, regcompnl, regexec, regsub, rregexec, rregsub, regerror \- regular expression +.SH SYNOPSIS +.B #include <u.h> +.br +.B #include <libc.h> +.br +.B #include <regexp.h> +.PP +.ta \w'\fLRegprog 'u +.B +Reprog *regcomp(char *exp) +.PP +.B +Reprog *regcomplit(char *exp) +.PP +.B +Reprog *regcompnl(char *exp) +.PP +.nf +.B +int regexec(Reprog *prog, char *string, Resub *match, int msize) +.PP +.nf +.B +void regsub(char *source, char *dest, int dlen, Resub *match, int msize) +.PP +.nf +.B +int rregexec(Reprog *prog, Rune *string, Resub *match, int msize) +.PP +.nf +.B +void rregsub(Rune *source, Rune *dest, int dlen, Resub *match, int msize) +.PP +.B +void regerror(char *msg) +.SH DESCRIPTION +.I Regcomp +compiles a +regular expression and returns +a pointer to the generated description. +The space is allocated by +.IR malloc (2) +and may be released by +.IR free . +Regular expressions are exactly as in +.IR regexp (6). +.PP +.I Regcomplit +is like +.I regcomp +except that all characters are treated literally. +.I Regcompnl +is like +.I regcomp +except that the +.B . +metacharacter matches all characters, including newlines. +.PP +.I Regexec +matches a null-terminated +.I string +against the compiled regular expression in +.IR prog . +If it matches, +.I regexec +returns +.B 1 +and fills in the array +.I match +with character pointers to the substrings of +.I string +that correspond to the +parenthesized subexpressions of +.IR exp : +.BI match[ i ].sp +points to the beginning and +.BI match[ i ].ep +points just beyond +the end of the +.IR i th +substring. +(Subexpression +.I i +begins at the +.IR i th +left parenthesis, counting from 1.) +Pointers in +.B match[0] +pick out the substring that corresponds to +the whole regular expression. +Unused elements of +.I match +are filled with zeros. +Matches involving +.LR * , +.LR + , +and +.L ? +are extended as far as possible. +The number of array elements in +.I match +is given by +.IR msize . +The structure of elements of +.I match +is: +.IP +.EX +typedef struct { + union { + char *sp; + Rune *rsp; + }; + union { + char *ep; + Rune *rep; + }; +} Resub; +.EE +.LP +If +.B match[0].sp +is nonzero on entry, +.I regexec +starts matching at that point within +.IR string . +If +.B match[0].ep +is nonzero on entry, +the last character matched is the one +preceding that point. +.PP +.I Regsub +places in +.I dest +a substitution instance of +.I source +in the context of the last +.I regexec +performed using +.IR match . +Each instance of +.BI \e n\f1, +where +.I n +is a digit, is replaced by the +string delimited by +.BI match[ n ].sp +and +.BI match[ n ].ep\f1. +Each instance of +.L & +is replaced by the string delimited by +.B match[0].sp +and +.BR match[0].ep . +The substitution will always be null terminated and +trimmed to fit into dlen bytes. +.PP +.IR Regerror , +called whenever an error is detected in +.IR regcomp , +writes the string +.I msg +on the standard error file and exits. +.I Regerror +can be replaced to perform +special error processing. +If the user supplied +.I regerror +returns rather than exits, +.I regcomp +will return 0. +.PP +.I Rregexec +and +.I rregsub +are variants of +.I regexec +and +.I regsub +that use strings of +.B Runes +instead of strings of +.BR chars . +With these routines, the +.I rsp +and +.I rep +fields of the +.I match +array elements should be used. +.SH SOURCE +.B /sys/src/libregexp +.SH "SEE ALSO" +.IR grep (1) +.SH DIAGNOSTICS +.I Regcomp +returns +.B 0 +for an illegal expression +or other failure. +.I Regexec +returns 0 +if +.I string +is not matched. +.SH BUGS +There is no way to specify or match a NUL character; NULs terminate patterns and strings. |