From: Eli Zaretskii <eliz@gnu.org>
To: bug-gnulib@gnu.org
Subject: swab wrapper fails mingw.org's MinGW compilation of GDB
Date: Mon, 29 Mar 2021 11:23:50 +0300 [thread overview]
Message-ID: <83czvimkq1.fsf@gnu.org> (raw)
The following snippet from Gnulib's unistd.h causes a compilation
error when building the current development version of GDB 11:
#if @GNULIB_MDA_SWAB@
/* On native Windows, map 'swab' to '_swab', so that -loldnames is not
required. In C++ with GNULIB_NAMESPACE, avoid differences between
platforms by defining GNULIB_NAMESPACE::creat always. */
# if defined _WIN32 && !defined __CYGWIN__
# if !(defined __cplusplus && defined GNULIB_NAMESPACE)
# undef swab
# define swab _swab
# endif
_GL_CXXALIAS_MDA (swab, void, (char *from, char *to, int n));
# else
_GL_CXXALIAS_SYS (swab, void, (const void *from, void *to, ssize_t n));
# endif
_GL_CXXALIASWARN (swab);
#endif
The problem is that mingw.org's MinGW uses a slightly different
prototype of _swab:
_CRTIMP __cdecl __MINGW_NOTHROW void _swab (const char *, char *, size_t);
So the difference between the prototypes causes this compilation error
in C++ programs:
CXX unittests/string_view-selftests.o
In file included from ./../gdbsupport/common-defs.h:86,
from ./defs.h:28,
from unittests/string_view-selftests.c:26:
./../gnulib/import/unistd.h: In member function 'gnulib::_gl_swab_wrapper::operator gnulib::_gl_swab_wrapper::type() const':
./../gnulib/import/unistd.h:2543:1: error: invalid conversion from 'void (__attribute__((cdecl)) *)(const char*, char*, size_t)' {aka 'void (__attribute__((cdecl)) *)(const char*, char*, unsigned int)'} to 'gnulib::_gl_swab_wrapper::type' {aka 'void (*)(char*, char*, int)'} [-fpermissive]
2543 | _GL_CXXALIAS_MDA (swab, void, (char *from, char *to, int n));
| ^~~~~~~~~~~~~~~~
| |
| void (__attribute__((cdecl)) *)(const char*, char*, size_t) {aka void (__attribute__((cdecl)) *)(const char*, char*, unsigned int)}
The suggested fix is as follows (__MINGW32_VERSION is defined by
mingw.org's MinGW, but not by MinGW64):
--- unistd.h~ 2021-03-29 09:15:08.782625000 +0300
+++ unistd.h 2021-03-29 10:19:46.485750000 +0300
@@ -2540,7 +2540,11 @@ _GL_WARN_ON_USE (sleep, "sleep is unport
# undef swab
# define swab _swab
# endif
+# if defined __MINGW32_VERSION
+_GL_CXXALIAS_MDA (swab, void, (const char *from, char *to, size_t n));
+# else
_GL_CXXALIAS_MDA (swab, void, (char *from, char *to, int n));
+# endif
# else
_GL_CXXALIAS_SYS (swab, void, (const void *from, void *to, ssize_t n));
# endif
next reply other threads:[~2021-03-29 8:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-29 8:23 Eli Zaretskii [this message]
2021-06-20 15:22 ` swab wrapper fails mingw.org's MinGW compilation of GDB Bruno Haible
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