regcmp(3)						     Library Functions Manual							 regcmp(3)

NAME

       regcmp, regex - Compile and execute regular expression

LIBRARY

       Standard C Library (libc.so, libc. a)

SYNOPSIS

       #include <libgen.h>

       char *regcmp(	  const char *string1,	    ... /*,	 (char *)0 */);

       char *regex(	 const char *re,      const char *subject,	... );

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       regcmp(), regex():  XPG4-UNIX

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

PARAMETERS

       Points  to the string that is to be matched or converted.  Points to a compiled regular expression string.  Points to the string that is to
       be matched against re.

DESCRIPTION

       The regcmp()  function compiles a regular expression consisting of the concatenated arguments and returns a pointer to the  compiled  form.
       The  end  of  arguments	is  indicated  by a null pointer.  The malloc() function is used to create space for the compiled form.  It is the
       responsibility of the process to free unneeded space so allocated.  A null pointer returned from regcmp() indicates an invalid argument.

       The regex() function executes a compiled pattern against the subject string. Additional arguments of type char must be  passed  to  receive
       matched subexpressions back.  A global character pointer, __loc1, points to the first matched character in the subject string.

       The  regcmp()  and regex() functions support the simple regular expressions which are defined in the grep(1) reference page, but the syntax
       and semantics are slightly different.  The following are the valid symbols and their associated	meanings:  The	left  and  right  bracket,
       asterisk,  period, and circumflex symbols retain their meanings as defined in the grep(1) reference page.  A dollar sign matches the end of
       the string; 
 matches a new line.  Used within brackets, the hyphen signifies an ASCII character range.  For example [a-z]  is	equivalent
       to  [abcd...xyz].   The	-  (hyphen)  can  represent  itself only if used as the first or last character.  For example, the character class
       expression []-] matches the characters ] (right bracket) and - (hyphen).  A regular expression followed by a + (plus  sign)  means  one	or
       more  times.  For example, [0-9]+ is equivalent to [0-9][0-9]*.	Integer values enclosed in {} braces indicate the number of times the pre-
       ceding regular expression can be applied.  The value m is the minimum number and u is a number, less than 256, which is the  maximum.   The
       syntax {m} indicates the exact number of times the regular expression can be applied.  The syntax {m,} is analogous to {m,infinity}.  The +
       (plus sign) and * (asterisk) operations are equivalent to {1,} and {0,}, respectively.  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 regular expressions are
       allowed.  The regex() function 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 symbols defined above are special characters, they must be escaped to be used as themselves.

NOTES

       The regcmp() and regex() interfaces are scheduled to be withdrawn from a future version of the X/Open CAE Specification.

       These interfaces are obsolete; they are guaranteed to function properly only in the C/POSIX locale and so should be avoided.  Use the POSIX
       regcomp() interface instead of regcmp() and regex().

RETURN VALUES

       Upon successful completion, the regcmp() function returns a pointer to the compiled regular  expression.   Otherwise,  a  null  pointer	is
       returned and errno may be set to indicate the error.

       Upon  successful  completion,  the  regex() function returns a pointer to the next unmatched character in the subject string.  Otherwise, a
       null pointer is returned.

RELATED INFORMATION

       Commands: grep(1)

       Functions: malloc(3), regcomp(3)

       Standards: standards(5) delim off

																	 regcmp(3)