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:Man regex

     These routines implement IEEE Std 1003.2 (``POSIX.2'') regular expressions
      (``RE''s); see re_format(7).  The regcomp() function compiles an RE, writte
     n as a string, into an internal form.  regexec() matches that internal form
      against a string and reports results.  regerror() transforms error codes f
     rom either into human-readable messages.  regfree() frees any dynamically-a
     llocated storage used by the internal form of an RE.

     REG_NOSPEC    Compile with recognition of all special characters turned off
     .  All characters are thus considered ordinary, so the ``RE'' is a literal
      string.  This is an extension, compatible with but not specified by IEEE St
     d 1003.2 (``POSIX.2''), and should be used with caution in software intende
     d to be portable to other systems.  REG_EXTENDED and REG_NOSPEC may not be
      used in the same call to regcomp().

     These routines implement IEEE Std 1003.2 (``POSIX.2'') regular expres-
     sions (``RE''s); see re_format(7).  The regcomp() function compiles an
     RE, written as a string, into an internal form.  regexec() matches that
     internal form against a string and reports results.  regerror() trans-
     forms error codes from either into human-readable messages.  regfree()
     frees any dynamically-allocated storage used by the internal form of an
     RE.

     REG_NOSPEC    Compile with recognition of all special characters turned
                   off.  All characters are thus considered ordinary, so the
                   ``RE'' is a literal string.  This is an extension, compati-
                   ble with but not specified by IEEE Std 1003.2
                   (``POSIX.2''), and should be used with caution in software
                   intended to be portable to other systems.  REG_EXTENDED and
                   REG_NOSPEC may not be used in the same call to regcomp().