xapian-core/common/msvcignoreinvalidparam.h

   1 /** @file  msvcignoreinvalidparam.h
   2  *  @brief Work around MSVC's unhelpful non-standard invalid parameter handling.
   3  */
   4 /* Copyright (C) 2006,2007,2008,2015,2018 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #ifndef XAPIAN_INCLUDED_MSVCIGNOREINVALIDPARAM_H
  22 #define XAPIAN_INCLUDED_MSVCIGNOREINVALIDPARAM_H
  23
  24 // __STDC_SECURE_LIB__ doesn't appear to be publicly documented, but including
  25 // in this check appears to be a good idea.  We cribbed this test from the
  26 // python sources - see, for example,
  27 // https://github.com/python/cpython/commit/74c3ea0a0f6599da7dd9a502b5a66aeb9512d8c3
  28 #if defined _MSC_VER && _MSC_VER >= 1400 && defined __STDC_SECURE_LIB__
  29 # include <cstdlib> // For _set_invalid_parameter_handler(), etc.
  30 # include <crtdbg.h> // For _CrtSetReportMode, etc.
  31
  32 /** A dummy invalid parameter handler which ignores the error. */
  33 static void dummy_handler(const wchar_t*,
  34                           const wchar_t*,
  35                           const wchar_t*,
  36                           unsigned int,
  37                           uintptr_t)
  38 {
  39 }
  40
  41 // Recent versions of MSVC call an "_invalid_parameter_handler" if a
  42 // CRT function receives an invalid parameter.  However, there are cases
  43 // where this is totally reasonable.  To avoid the application dying,
  44 // you just need to instantiate the MSVCIgnoreInvalidParameter class in
  45 // the scope where you want MSVC to ignore invalid parameters.
  46 class MSVCIgnoreInvalidParameter {
  47     _invalid_parameter_handler old_handler;
  48     int old_report_mode;
  49
  50   public:
  51     MSVCIgnoreInvalidParameter() {
  52         // Install a dummy handler to avoid the program dying.
  53         old_handler = _set_invalid_parameter_handler(dummy_handler);
  54         // Make sure that no dialog boxes appear.
  55         old_report_mode = _CrtSetReportMode(_CRT_ASSERT, 0);
  56     }
  57
  58     ~MSVCIgnoreInvalidParameter() {
  59         // Restore the previous settings.
  60         _set_invalid_parameter_handler(old_handler);
  61         _CrtSetReportMode(_CRT_ASSERT, old_report_mode);
  62     }
  63 };
  64 #else
  65 // Mingw seems to be free of this insanity, so for mingw, older MSVC versions,
  66 // and other platforms define a dummy class to allow MSVCIgnoreInvalidParameter
  67 // to be used unconditionally.
  68 struct MSVCIgnoreInvalidParameter {
  69     // Provide an explicit constructor so this isn't a POD struct - this seems
  70     // to prevent GCC warning about an unused variable whenever we instantiate
  71     // this class.
  72     MSVCIgnoreInvalidParameter() { }
  73 };
  74 #endif
  75
  76 #endif