/**************************************************      Perl-Compatible Regular Expressions       **************************************************//* PCRE is a library of functions to support regular expressions whose syntaxand semantics are as close as possible to those of the Perl 5 language.                       Written by Philip Hazel           Copyright (c) 1997-2007 University of Cambridge-----------------------------------------------------------------------------Redistribution and use in source and binary forms, with or withoutmodification, are permitted provided that the following conditions are met:    * Redistributions of source code must retain the above copyright notice,      this list of conditions and the following disclaimer.    * Redistributions in binary form must reproduce the above copyright      notice, this list of conditions and the following disclaimer in the      documentation and/or other materials provided with the distribution.    * Neither the name of the University of Cambridge nor the names of its      contributors may be used to endorse or promote products derived from      this software without specific prior written permission.THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THEIMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSEARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BELIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, ORCONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OFSUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESSINTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER INCONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THEPOSSIBILITY OF SUCH DAMAGE.-----------------------------------------------------------------------------*//* This module contains the external function pcre_version(), which returns astring that identifies the PCRE version that is in use. */#ifdef HAVE_CONFIG_H#include "config.h"#endif#include "pcre_internal.h"/**************************************************          Return version string                 **************************************************//* These macros are the standard way of turning unquoted text into C strings.They allow macros like PCRE_MAJOR to be defined without quotes, which isconvenient for user programs that want to test its value. */#define STRING(a)  # a#define XSTRING(s) STRING(s)/* A problem turned up with PCRE_PRERELEASE, which is defined empty forproduction releases. Originally, it was used naively in this code:  return XSTRING(PCRE_MAJOR)         "." XSTRING(PCRE_MINOR)             XSTRING(PCRE_PRERELEASE)         " " XSTRING(PCRE_DATE);However, when PCRE_PRERELEASE is empty, this leads to an attempted expansion ofSTRING(). The C standard states: "If (before argument substitution) anyargument consists of no preprocessing tokens, the behavior is undefined." Itturns out the gcc treats this case as a single empty string - which is what wereally want - but Visual C grumbles about the lack of an argument for themacro. Unfortunately, both are within their rights. To cope with both ways ofhandling this, I had resort to some messy hackery that does a test at run time.I could find no way of detecting that a macro is defined as an empty string atpre-processor time. This hack uses a standard trick for avoiding callingthe STRING macro with an empty argument when doing the test. */PCRE_EXP_DEFN const char *pcre_version(void){return (XSTRING(Z PCRE_PRERELEASE)[1] == 0)?  XSTRING(PCRE_MAJOR.PCRE_MINOR PCRE_DATE) :  XSTRING(PCRE_MAJOR.PCRE_MINOR) XSTRING(PCRE_PRERELEASE PCRE_DATE);}/* End of pcre_version.c */