HP-UX Reference (11i v2 07/12) - 3 Library Functions N-Z (vol 7)

r
regcmp(3X) regcmp(3X)
(TO BE OBSOLETED)
NAME
regcmp(), regex() - compile and execute regular expression
SYNOPSIS
#include <libgen.h>
char *regcmp(
const char *string1,
/* string2, */ ...
/*, (char *)0 */
);
char *regex(const char *re, const char *subject, ...);
extern char *_ _loc1;
Remarks
The ANSI C ", ..." construct denotes a variable length argument list whose optional [or required]
members are given in the associated comment (
/* */).
Features documented in this manual entry are obsolescent and may be removed in a future HP-UX release.
Use of regcomp(3C) instead is recommended.
DESCRIPTION
regcmp() compiles a regular expression and returns a pointer to the compiled form. malloc(3C) is used
to create space for the vector. It is the user’s responsibility to free unneeded space so allocated. A NULL
return from
regcmp() indicates an incorrect argument.
regex() executes a compiled pattern against the subject string. Additional arguments are passed to
receive values back. regex() returns NULL on failure, or a pointer to the next unmatched character on
success. A global character pointer _ _loc1 points to where the match began.
regcmp() and
regex() were largely borrowed from the editor, ed(1); however, the syntax and semantics have been
changed slightly. The following are the valid symbols and their associated meanings:
[]*.ˆ These symbols retain their current meaning.
$ Matches the end of the string; \n matches a new-line.
- Used within brackets the hyphen signifies a character range. For example,
[a-z] is
equivalent to
[abcd...xyz]. The - can represent itself only if used as the first or
last character. For example, the character class expression []-] matches the char-
acters ] and -.
+ A regular expression followed by + means one or more times. For example, [0-9]+
is equivalent to [0-9][0-9]* .
{m}{m,} {m,u}
Integer values enclosed in {}indicate the number of times the preceding regular
expression can be applied. The value m is the minimum number and u is a maximum
number, which must be no greater than 256. The syntax {m} indicates the exact
number of times the regular expression can be applied. The syntax
{m,} is analo-
gous to {m,infinity}. The plus (+) and asterisk (*) operations are equivalent to {1,}
and {0,} respectively.
( ...)$n The value of the enclosed regular expression is returned. The value is stored in the
(n+1)th argument following the subject argument. A maximum of ten enclosed regu-
lar expressions are allowed. regex() makes its assignments unconditionally.
( ...) Parentheses are used for grouping. An operator, such as *, +,or{}, can work on a
single character or a regular expression enclosed in parentheses. For example,
(a∗(cb+) ∗)$0.
Since all of the above defined symbols are special characters, they must be escaped to be used as them-
selves.
EXAMPLES
Match a leading new-line in the subject string to which the cursor points.
298 Hewlett-Packard Company − 1 − HP-UX 11i Version 2: December 2007 Update