xapian-core  1.4.20
setenv.h
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1 
4 /* Copyright (C) 2019 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_SETENV_H
22 #define XAPIAN_INCLUDED_SETENV_H
23 
24 #ifndef PACKAGE
25 # error config.h must be included first in each C++ source file
26 #endif
27 
28 #include <stdlib.h>
29 
30 #ifdef HAVE_SETENV
31 // setenv() provided by the system.
32 #elif defined HAVE__PUTENV_S
33 # if !HAVE_DECL__PUTENV_S
34 // Mingw 3.20 doesn't declare this, but it's in the Microsoft C runtime DLL.
35 extern "C" int _putenv_s(const char*, const char*);
36 # endif
37 
38 // Use a lambda function to give us a block scope to use static_assert in
39 // while still being able to return a result.
40 # define setenv(NAME, VALUE, OVERWRITE) ([]() { \
41  static_assert((OVERWRITE), "OVERWRITE must be non-zero constant"); \
42  (void)(OVERWRITE); \
43  return _putenv_s((NAME), (VALUE)) ? -1 : 0; \
44 })()
45 
46 #endif
47 
48 #endif // XAPIAN_INCLUDED_SETENV_H