[libcxx] r249798 - Split <stdio.h> out of <cstdio>.
Eric Fiselier via cfe-commits
cfe-commits at lists.llvm.org
Tue Oct 13 14:12:41 PDT 2015
I would rather not do this if possible but I understand why we need to do
it.
Richard is there a cost associated with the 'extern "C++"' construct? or by
forcing the compiler to switch modes in general?
On Mon, Oct 12, 2015 at 12:27 PM, Richard Smith <richard at metafoo.co.uk>
wrote:
> On Mon, Oct 12, 2015 at 9:41 AM, Steven Wu via cfe-commits <
> cfe-commits at lists.llvm.org> wrote:
>
>> Hi Richard
>>
>> Your splitting seems causing problem when using extern "C". Here is a
>> test case:
>>
>> $ cat test.cpp
>> #ifdef __cplusplus
>> extern "C" {
>> #endif
>> #include <stdio.h>
>> #ifdef __cplusplus
>> }
>> #endif
>>
>> Error:
>> clang -fsyntax-only test.cpp
>> In file included from test.cpp:4:
>> In file included from /usr/bin/../include/c++/v1/stdio.h:102:
>> /usr/bin/../include/c++/v1/__config:593:1: error:
>> templates must have C++ linkage
>> template <bool> struct __static_assert_test;
>> ^~~~~~~~~~~~~~~
>> /usr/bin/../include/c++/v1/__config:594:20: error:
>> explicit specialization of non-template struct
>> '__static_assert_test'
>> template <> struct __static_assert_test<true> {};
>> ^ ~~~~~~
>> /usr/bin/../include/c++/v1/__config:595:1: error:
>> templates must have C++ linkage
>> template <unsigned> struct __static_assert_check {};
>> ^~~~~~~~~~~~~~~~~~~
>> 3 errors generated.
>>
>> Because the code is actually compiled in C++, the guard in the header
>> failed to exclude the templates. In the meantime, I don't know if there are
>> ways to detect the header is in extern "C".
>>
>
> This was supposed to work, but apparently I only tested it when compiling
> as C++11; the static_assert emulation in C++98 mode needs some massaging to
> cope with this.
>
> Eric, Marshall: Are you OK with the attached patch? The idea is to make
> <__config> be fine to include in extern "C" or extern "C++" modes (and
> likewise for the <foo.h> headers). This is something that comes up pretty
> often in practice (people wrap an include of a C header in 'extern "C"',
> and that C header includes a <foo.h> file that libc++ provides).
>
>
>> Steven
>>
>>
>> > On Oct 8, 2015, at 6:29 PM, Richard Smith via cfe-commits <
>> cfe-commits at lists.llvm.org> wrote:
>> >
>> > Author: rsmith
>> > Date: Thu Oct 8 20:29:09 2015
>> > New Revision: 249798
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=249798&view=rev
>> > Log:
>> > Split <stdio.h> out of <cstdio>.
>> >
>> > As with <stddef.h>, skip our custom header if __need_FILE or
>> __need___FILE is defined.
>> >
>> > Added:
>> > libcxx/trunk/include/stdio.h
>> > - copied, changed from r249736, libcxx/trunk/include/cstdio
>> > Modified:
>> > libcxx/trunk/include/cstdio
>> > libcxx/trunk/test/std/depr/depr.c.headers/stdio_h.pass.cpp
>> >
>> > Modified: libcxx/trunk/include/cstdio
>> > URL:
>> http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/cstdio?rev=249798&r1=249797&r2=249798&view=diff
>> >
>> ==============================================================================
>> > --- libcxx/trunk/include/cstdio (original)
>> > +++ libcxx/trunk/include/cstdio Thu Oct 8 20:29:09 2015
>> > @@ -103,16 +103,6 @@ void perror(const char* s);
>> > #pragma GCC system_header
>> > #endif
>> >
>> > -// snprintf
>> > -#if defined(_LIBCPP_MSVCRT)
>> > -#include "support/win32/support.h"
>> > -#endif
>> > -
>> > -#undef getc
>> > -#undef putc
>> > -#undef clearerr
>> > -#undef feof
>> > -#undef ferror
>> > _LIBCPP_BEGIN_NAMESPACE_STD
>> >
>> > using ::FILE;
>> >
>> > Copied: libcxx/trunk/include/stdio.h (from r249736,
>> libcxx/trunk/include/cstdio)
>> > URL:
>> http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/stdio.h?p2=libcxx/trunk/include/stdio.h&p1=libcxx/trunk/include/cstdio&r1=249736&r2=249798&rev=249798&view=diff
>> >
>> ==============================================================================
>> > --- libcxx/trunk/include/cstdio (original)
>> > +++ libcxx/trunk/include/stdio.h Thu Oct 8 20:29:09 2015
>> > @@ -1,5 +1,5 @@
>> > // -*- C++ -*-
>> > -//===---------------------------- cstdio
>> ----------------------------------===//
>> > +//===---------------------------- stdio.h
>> ---------------------------------===//
>> > //
>> > // The LLVM Compiler Infrastructure
>> > //
>> > @@ -8,11 +8,19 @@
>> > //
>> >
>> //===----------------------------------------------------------------------===//
>> >
>> > -#ifndef _LIBCPP_CSTDIO
>> > -#define _LIBCPP_CSTDIO
>> > +#if defined(__need_FILE) || defined(__need___FILE)
>> > +
>> > +#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
>> > +#pragma GCC system_header
>> > +#endif
>> > +
>> > +#include_next <stdio.h>
>> > +
>> > +#elif !defined(_LIBCPP_STDIO_H)
>> > +#define _LIBCPP_STDIO_H
>> >
>> > /*
>> > - cstdio synopsis
>> > + stdio.h synopsis
>> >
>> > Macros:
>> >
>> > @@ -33,9 +41,6 @@ Macros:
>> > stdin
>> > stdout
>> >
>> > -namespace std
>> > -{
>> > -
>> > Types:
>> >
>> > FILE
>> > @@ -92,20 +97,23 @@ void clearerr(FILE* stream);
>> > int feof(FILE* stream);
>> > int ferror(FILE* stream);
>> > void perror(const char* s);
>> > -
>> > -} // std
>> > */
>> >
>> > #include <__config>
>> > -#include <stdio.h>
>> >
>> > #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
>> > #pragma GCC system_header
>> > #endif
>> >
>> > +#include_next <stdio.h>
>> > +
>> > +#ifdef __cplusplus
>> > +
>> > // snprintf
>> > #if defined(_LIBCPP_MSVCRT)
>> > +extern "C++" {
>> > #include "support/win32/support.h"
>> > +}
>> > #endif
>> >
>> > #undef getc
>> > @@ -113,72 +121,7 @@ void perror(const char* s);
>> > #undef clearerr
>> > #undef feof
>> > #undef ferror
>> > -_LIBCPP_BEGIN_NAMESPACE_STD
>> > -
>> > -using ::FILE;
>> > -using ::fpos_t;
>> > -using ::size_t;
>> > -
>> > -using ::fclose;
>> > -using ::fflush;
>> > -using ::setbuf;
>> > -using ::setvbuf;
>> > -using ::fprintf;
>> > -using ::fscanf;
>> > -using ::snprintf;
>> > -using ::sprintf;
>> > -using ::sscanf;
>> > -#ifndef _LIBCPP_MSVCRT
>> > -using ::vfprintf;
>> > -using ::vfscanf;
>> > -using ::vsscanf;
>> > -#endif // _LIBCPP_MSVCRT
>> > -using ::vsnprintf;
>> > -using ::vsprintf;
>> > -using ::fgetc;
>> > -using ::fgets;
>> > -using ::fputc;
>> > -using ::fputs;
>> > -using ::getc;
>> > -using ::putc;
>> > -using ::ungetc;
>> > -using ::fread;
>> > -using ::fwrite;
>> > -using ::fgetpos;
>> > -using ::fseek;
>> > -using ::fsetpos;
>> > -using ::ftell;
>> > -using ::rewind;
>> > -using ::clearerr;
>> > -using ::feof;
>> > -using ::ferror;
>> > -using ::perror;
>> > -
>> > -#ifndef _LIBCPP_HAS_NO_GLOBAL_FILESYSTEM_NAMESPACE
>> > -using ::fopen;
>> > -using ::freopen;
>> > -using ::remove;
>> > -using ::rename;
>> > -using ::tmpfile;
>> > -using ::tmpnam;
>> > -#endif
>> >
>> > -#ifndef _LIBCPP_HAS_NO_STDIN
>> > -using ::getchar;
>> > -#if _LIBCPP_STD_VER <= 11
>> > -using ::gets;
>> > #endif
>> > -using ::scanf;
>> > -using ::vscanf;
>> > -#endif
>> > -
>> > -#ifndef _LIBCPP_HAS_NO_STDOUT
>> > -using ::printf;
>> > -using ::putchar;
>> > -using ::puts;
>> > -using ::vprintf;
>> > -#endif
>> > -
>> > -_LIBCPP_END_NAMESPACE_STD
>> >
>> > -#endif // _LIBCPP_CSTDIO
>> > +#endif // _LIBCPP_STDIO_H
>> >
>> > Modified: libcxx/trunk/test/std/depr/depr.c.headers/stdio_h.pass.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/depr/depr.c.headers/stdio_h.pass.cpp?rev=249798&r1=249797&r2=249798&view=diff
>> >
>> ==============================================================================
>> > --- libcxx/trunk/test/std/depr/depr.c.headers/stdio_h.pass.cpp
>> (original)
>> > +++ libcxx/trunk/test/std/depr/depr.c.headers/stdio_h.pass.cpp Thu Oct
>> 8 20:29:09 2015
>> > @@ -13,6 +13,26 @@
>> > #include <type_traits>
>> > #include "test_macros.h"
>> >
>> > +#ifdef getc
>> > +#error getc is defined
>> > +#endif
>> > +
>> > +#ifdef putc
>> > +#error putc is defined
>> > +#endif
>> > +
>> > +#ifdef clearerr
>> > +#error clearerr is defined
>> > +#endif
>> > +
>> > +#ifdef feof
>> > +#error feof is defined
>> > +#endif
>> > +
>> > +#ifdef ferror
>> > +#error ferror is defined
>> > +#endif
>> > +
>> > #ifndef BUFSIZ
>> > #error BUFSIZ not defined
>> > #endif
>> >
>> >
>> > _______________________________________________
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>>
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