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Annotation of embedaddon/pcre/pcre_version.c, revision 1.1

1.1     ! misho       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) 1997-2008 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: #ifdef HAVE_CONFIG_H
        !            46: #include "config.h"
        !            47: #endif
        !            48: 
        !            49: #include "pcre_internal.h"
        !            50: 
        !            51: 
        !            52: /*************************************************
        !            53: *          Return version string                 *
        !            54: *************************************************/
        !            55: 
        !            56: /* These macros are the standard way of turning unquoted text into C strings.
        !            57: They allow macros like PCRE_MAJOR to be defined without quotes, which is
        !            58: convenient for user programs that want to test its value. */
        !            59: 
        !            60: #define STRING(a)  # a
        !            61: #define XSTRING(s) STRING(s)
        !            62: 
        !            63: /* A problem turned up with PCRE_PRERELEASE, which is defined empty for
        !            64: production releases. Originally, it was used naively in this code:
        !            65: 
        !            66:   return XSTRING(PCRE_MAJOR)
        !            67:          "." XSTRING(PCRE_MINOR)
        !            68:              XSTRING(PCRE_PRERELEASE)
        !            69:          " " XSTRING(PCRE_DATE);
        !            70: 
        !            71: However, when PCRE_PRERELEASE is empty, this leads to an attempted expansion of
        !            72: STRING(). The C standard states: "If (before argument substitution) any
        !            73: argument consists of no preprocessing tokens, the behavior is undefined." It
        !            74: turns out the gcc treats this case as a single empty string - which is what we
        !            75: really want - but Visual C grumbles about the lack of an argument for the
        !            76: macro. Unfortunately, both are within their rights. To cope with both ways of
        !            77: handling this, I had resort to some messy hackery that does a test at run time.
        !            78: I could find no way of detecting that a macro is defined as an empty string at
        !            79: pre-processor time. This hack uses a standard trick for avoiding calling
        !            80: the STRING macro with an empty argument when doing the test. */
        !            81: 
        !            82: PCRE_EXP_DEFN const char * PCRE_CALL_CONVENTION
        !            83: pcre_version(void)
        !            84: {
        !            85: return (XSTRING(Z PCRE_PRERELEASE)[1] == 0)?
        !            86:   XSTRING(PCRE_MAJOR.PCRE_MINOR PCRE_DATE) :
        !            87:   XSTRING(PCRE_MAJOR.PCRE_MINOR) XSTRING(PCRE_PRERELEASE PCRE_DATE);
        !            88: }
        !            89: 
        !            90: /* End of pcre_version.c */