Open System Services Library Calls Reference Manual (G06.28+, H06.05+)

compile(3) OSS Library Calls Reference Manual

NAME

compile - Compiles regular expressions

LIBRARY

None. This application program interface is implemented as a macro.

SYNOPSIS

#deﬁne INIT declarations

#deﬁne GETC() getc code

#deﬁne PEEKC() peekc code

#deﬁne UNGETC(c) ungetc code

#deﬁne RETURN(ptr) return code

#deﬁne ERROR(val) error code

#include <regexp.h>

char *compile (

char *instring,

char *expbuf,

const char *endbuf,

int eof);

extern char *loc1, *loc2, *locs;

PARAMETERS

c The value returned by the next call to the GETC() and PEEKC() macros.

ptr Speciﬁes a pointer to the character following the last character of the compiled

regular expression.

val Speciﬁes an error value.

instring Speciﬁes a string to be passed to the compile() macro. The instring parameter is

never used explicitly by the compile() macro, but you can use it in your macros.

For example, you may want to pass the string containing a pattern as the instring

parameter to the compile() macro and use the INIT( ) macro to set a pointer to

the beginning of this string. When your macros do not use instring, call the

compile() macro with a value of ((char *) 0) for this parameter.

expbuf Points to a character array where the compiled regular expression is stored.

endbuf Points to the location that immediately follows the character array where the

compiled regular expression is stored. When the compiled expression cannot be

contained in (endbuf-expbuf) number of bytes, a call to the ERROR(50) macro

is made.

eof Speciﬁes the character that marks the end of the regular expression. For example,

in ed this character is usually a / (slash).

DESCRIPTION

The compile(), advance(), and step() macros are used for general-purpose expression matching.

The compile() macro takes a simple regular expression as input and produces a compiled expres-

sion that can be used with the step() and advance() macros.

The following six macros, used in the compile() macro, must be deﬁned before the #include

<regexp.h> statement in programs. The GETC(),PEEKC(), and UNGETC() macros operate

on the regular expression provided as input for the compile() macro.

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