2 Copyright (C) 2012 Paul Davis
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 #include "pbd/compose.h"
26 #include "pbd/debug.h"
27 #include "pbd/error.h"
28 #include "pbd/locale_guard.h"
32 /* Neither C nor C++ pick up a user's preferred locale choice without the
33 * application actively taking steps to make this happen.
35 * For C: setlocale (LC_ALL, "");
36 * For C++ (assuming that the C version was called):
37 * std::locale::global (std::locale (setlocale (LC_ALL, 0)));
39 * The application needs to make these calls, probably in main().
41 * Setting the C++ locale will change the C locale, but not the other way 'round.
42 * and some plugin may change either behind our back.
45 LocaleGuard::LocaleGuard ()
48 /* A LocaleGuard object ensures that the
49 * LC_NUMERIC/std::locale::numeric aspect of the C and C++ locales are
50 * set to "C" during its lifetime, so that printf/iostreams use a
51 * portable format for numeric output (i.e. 1234.5 is always 1234.5 and
52 * not sometimes 1234,5, as it would be in fr or de locales)
55 char const * const current_c_locale = setlocale (LC_NUMERIC, 0);
57 if (strcmp ("C", current_c_locale) != 0) {
59 old_c_locale = strdup (current_c_locale);
62 /* set the C++ global/default locale to whatever we are using
63 * now, but with "C" numeric handling.
65 * this also sets the C locale, so no additional call to setlocale() is required.
68 std::locale::global (std::locale (old_cpp_locale, "C", std::locale::numeric));
69 pre_cpp_locale = std::locale();
70 DEBUG_TRACE (DEBUG::Locale, string_compose ("LG: change C & C++ locale from '%1' => %2\n", old_cpp_locale.name(), pre_cpp_locale.name()));
73 /* Apple in particular have historically done a
74 * terrible job supporting setlocale and even more so
75 * with the C++ API. Using any locale other than "C" or
76 * "POSIX" will fail, and in the case of the C++ API,
77 * will throw an exception. In that case, just try to
78 * use setlocale() to reset *only* the numeric aspect
79 * of the current locale settings back to "C", which is
80 * likely to work everywhere.
83 setlocale (LC_NUMERIC, "C");
84 pre_cpp_locale = std::locale();
85 DEBUG_TRACE (DEBUG::Locale, string_compose ("LG: C++ locale API failed, change just C locale from '%1' => 'C' (C++ locale is %2)\n", old_c_locale, pre_cpp_locale.name()));
91 LocaleGuard::~LocaleGuard ()
93 char const * current_c_locale = setlocale (LC_NUMERIC, 0);
94 std::locale current_cpp_locale;
96 if (current_cpp_locale != pre_cpp_locale) {
98 PBD::warning << string_compose ("LocaleGuard: someone (a plugin) changed the C++ locale from\n\t%1\nto\n\t%2\n, expect non-portable session files. Decimal OK ? %2",
99 old_cpp_locale.name(), current_cpp_locale.name(),
100 (std::use_facet<std::numpunct<char> >(std::locale()).decimal_point() == '.'))
104 /* this resets C & C++ locales */
105 std::locale::global (old_cpp_locale);
106 DEBUG_TRACE (DEBUG::Locale, string_compose ("LG: restore C & C++ locale: '%1'\n", std::locale().name()));
108 /* see comments in the constructor regarding the
111 * This should restore restore numeric handling back to
112 * the default (which may reflect user
113 * preferences). This probably can't fail, because
114 * old_c_locale was already in use during the
115 * constructor for this object.
117 * Still ... Apple ... locale support ... just sayin' ....
119 setlocale (LC_NUMERIC, old_c_locale);
120 DEBUG_TRACE (DEBUG::Locale, string_compose ("LG: C++ locale API failed, restore C locale from %1 to\n'%2'\n(C++ is '%3')\n", current_c_locale, old_c_locale, std::locale().name()));
123 } else if (old_c_locale && (strcmp (current_c_locale, old_c_locale) != 0)) {
125 /* reset only the C locale */
126 setlocale (LC_NUMERIC, old_c_locale);
127 DEBUG_TRACE (DEBUG::Locale, string_compose ("LG: restore C locale from %1 to\n'%2'\n(C++ is '%3')\n", current_c_locale, old_c_locale, std::locale().name()));
130 free (const_cast<char*> (old_c_locale));