Load pcre-1.00 into code/trunk.

git-svn-id: svn://vcs.exim.org/pcre/code/trunk@3 2f5784b3-3f2a-0410-8824-cb99058d5e15

1 files changed, 135 insertions, 0 deletions

diff --git a/pcreposix.3 b/pcreposix.3
new file mode 100644
index 0000000..2c907e7
--- /dev/null
+++ b/pcreposix.3
@@ -0,0 +1,135 @@
+.TH PCRE 3
+.SH NAME
+pcreposix - POSIX API for Perl-compatible regular expressions.
+.SH SYNOPSIS
+.B #include <pcreposix.h>
+.PP
+.SM
+.br
+.B int regcomp(regex_t *\fIpreg\fR, const char *\fIpattern\fR,
+.ti +5n
+.B int \fIcflags\fR);
+.PP
+.br
+.B int regexec(regex_t *\fIpreg\fR, const char *\fIstring\fR,
+.ti +5n
+.B size_t \fInmatch\fR, regmatch_t \fIpmatch\fR[], int \fIeflags\fR);
+.PP
+.br
+.B size_t regerror(int \fIerrcode\fR, const regex_t *\fIpreg\fR,
+.ti +5n
+.B char *\fIerrbuf\fR, size_t \fIerrbuf_size\fR);
+.PP
+.br
+.B void regfree(regex_t *\fIpreg\fR);
+
+
+.SH DESCRIPTION
+This set of functions provides a POSIX-style API to the PCRE regular expression
+package. See \fBpcre (3)\fR for a description of the native API, which contains
+additional functionality. The functions described here are just wrapper
+functions that ultimately call the native API.
+
+As I am pretty ignorant about POSIX, these functions must be considered as
+experimental. I have implemented only those option bits that can be reasonably
+mapped to PCRE native options. Other POSIX options are not even defined. It may
+be that it is useful to define, but ignore, other options. Feedback from more
+knowledgeable folk may cause this kind of detail to change.
+
+When PCRE is called via these functions, it is only the API that is POSIX-like
+in style. The syntax and semantics of the regular expressions themselves are
+still those of Perl, subject to the setting of various PCRE options, as
+described below.
+
+The header for these functions is supplied as \fBpcreposix.h\fR to avoid any
+potential clash with other POSIX libraries. It can, of course, be renamed or
+aliased as \fBregex.h\fR, which is the "correct" name. It provides two
+structure types, \fIregex_t\fR for compiled internal forms, and
+\fIregmatch_t\fR for returning captured substrings. It also defines some
+constants whose names start with "REG_"; these are used for setting options and
+identifying error codes.
+
+
+.SH COMPILING A PATTERN
+
+The function \fBregcomp()\fR is called to compile a pattern into an
+internal form. The pattern is a C string terminated by a binary zero, and
+is passed in the argument \fIpattern\fR. The \fIpreg\fR argument is a pointer
+to a regex_t structure which is used as a base for storing information about
+the compiled expression.
+
+The argument \fIcflags\fR is either zero, or contains one or more of the bits
+defined by the following macros:
+
+  REG_ICASE
+
+The PCRE_CASELESS option is set when the expression is passed for compilation
+to the native function.
+
+  REG_NEWLINE
+
+The PCRE_MULTILINE option is set when the expression is passed for compilation
+to the native function.
+
+The yield of \fBregcomp()\fR is zero on success, and non-zero otherwise. The
+\fIpreg\fR structure is filled in on success, and one member of the structure
+is publicized: \fIre_nsub\fR contains the number of capturing subpatterns in
+the regular expression. Various error codes are defined in the header file.
+
+
+.SH MATCHING A PATTERN
+The function \fBregexec()\fR is called to match a pre-compiled pattern
+\fIpreg\fR against a given \fIstring\fR, which is terminated by a zero byte,
+subject to the options in \fIeflags\fR. These can be:
+
+  REG_NOTBOL
+
+The PCRE_NOTBOL option is set when calling the underlying PCRE matching
+function.
+
+  REG_NOTEOL
+
+The PCRE_NOTEOL option is set when calling the underlying PCRE matching
+function.
+
+The portion of the string that was matched, and also any captured substrings,
+are returned via the \fIpmatch\fR argument, which points to an array of
+\fInmatch\fR structures of type \fIregmatch_t\fR, containing the members
+\fIrm_so\fR and \fIrm_eo\fR. These contain the offset to the first character of
+each substring and the offset to the first character after the end of each
+substring, respectively. The 0th element of the vector relates to the entire
+portion of \fIstring\fR that was matched; subsequent elements relate to the
+capturing subpatterns of the regular expression. Unused entries in the array
+have both structure members set to -1.
+
+A successful match yields a zero return; various error codes are defined in the
+header file, of which REG_NOMATCH is the "expected" failure code.
+
+
+.SH ERROR MESSAGES
+The \fBregerror()\fR function maps a non-zero errorcode from either
+\fBregcomp\fR or \fBregexec\fR to a printable message. If \fIpreg\fR is not
+NULL, the error should have arisen from the use of that structure. A message
+terminated by a binary zero is placed in \fIerrbuf\fR. The length of the
+message, including the zero, is limited to \fIerrbuf_size\fR. The yield of the
+function is the size of buffer needed to hold the whole message.
+
+
+.SH STORAGE
+Compiling a regular expression causes memory to be allocated and associated
+with the \fIpreg\fR structure. The function \fBregfree()\fR frees all such
+memory, after which \fIpreg\fR may no longer be used as a compiled expression.
+
+
+.SH AUTHOR
+Philip Hazel <ph10@cam.ac.uk>
+.br
+University Computing Service,
+.br
+New Museums Site,
+.br
+Cambridge CB2 3QG, England.
+.br
+Phone: +44 1223 334714
+
+Copyright (c) 1997 University of Cambridge.