1                 : /*************************************************
       2                 : *      Perl-Compatible Regular Expressions       *
       3                 : *************************************************/
       4                 : 
       5                 : /* PCRE is a library of functions to support regular expressions whose syntax
       6                 : and semantics are as close as possible to those of the Perl 5 language.
       7                 : 
       8                 :                        Written by Philip Hazel
       9                 :            Copyright (c) 1997-2006 University of Cambridge
      10                 : 
      11                 : -----------------------------------------------------------------------------
      12                 : Redistribution and use in source and binary forms, with or without
      13                 : modification, are permitted provided that the following conditions are met:
      14                 : 
      15                 :     * Redistributions of source code must retain the above copyright notice,
      16                 :       this list of conditions and the following disclaimer.
      17                 : 
      18                 :     * Redistributions in binary form must reproduce the above copyright
      19                 :       notice, this list of conditions and the following disclaimer in the
      20                 :       documentation and/or other materials provided with the distribution.
      21                 : 
      22                 :     * Neither the name of the University of Cambridge nor the names of its
      23                 :       contributors may be used to endorse or promote products derived from
      24                 :       this software without specific prior written permission.
      25                 : 
      26                 : THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
      27                 : AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      28                 : IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
      29                 : ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
      30                 : LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
      31                 : CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
      32                 : SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
      33                 : INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
      34                 : CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
      35                 : ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
      36                 : POSSIBILITY OF SUCH DAMAGE.
      37                 : -----------------------------------------------------------------------------
      38                 : */
      39                 : 
      40                 : 
      41                 : /* This module contains the external function pcre_version(), which returns a
      42                 : string that identifies the PCRE version that is in use. */
      43                 : 
      44                 : 
      45                 : #include "pcre_internal.h"
      46                 : 
      47                 : 
      48                 : /*************************************************
      49                 : *          Return version string                 *
      50                 : *************************************************/
      51                 : 
      52                 : /* These macros are the standard way of turning unquoted text into C strings.
      53                 : They allow macros like PCRE_MAJOR to be defined without quotes, which is
      54                 : convenient for user programs that want to test its value. */
      55                 : 
      56                 : #define STRING(a)  # a
      57                 : #define XSTRING(s) STRING(s)
      58                 : 
      59                 : /* A problem turned up with PCRE_PRERELEASE, which is defined empty for
      60                 : production releases. Originally, it was used naively in this code:
      61                 : 
      62                 :   return XSTRING(PCRE_MAJOR)
      63                 :          "." XSTRING(PCRE_MINOR)
      64                 :              XSTRING(PCRE_PRERELEASE)
      65                 :          " " XSTRING(PCRE_DATE);
      66                 : 
      67                 : However, when PCRE_PRERELEASE is empty, this leads to an attempted expansion of
      68                 : STRING(). The C standard states: "If (before argument substitution) any
      69                 : argument consists of no preprocessing tokens, the behavior is undefined." It
      70                 : turns out the gcc treats this case as a single empty string - which is what we
      71                 : really want - but Visual C grumbles about the lack of an argument for the
      72                 : macro. Unfortunately, both are within their rights. To cope with both ways of
      73                 : handling this, I had resort to some messy hackery that does a test at run time.
      74                 : I could find no way of detecting that a macro is defined as an empty string at
      75                 : pre-processor time. This hack uses a standard trick for avoiding calling
      76                 : the STRING macro with an empty argument when doing the test. */
      77                 : 
      78                 : PCRE_DATA_SCOPE const char *
      79                 : pcre_version(void)
      80               0 : {
      81               0 : return (XSTRING(Z PCRE_PRERELEASE)[1] == 0)?
      82                 :   XSTRING(PCRE_MAJOR.PCRE_MINOR PCRE_DATE) :
      83                 :   XSTRING(PCRE_MAJOR.PCRE_MINOR) XSTRING(PCRE_PRERELEASE PCRE_DATE);
      84                 : }
      85                 : 
      86                 : /* End of pcre_version.c */