| /* Retrieve information about a FILE stream. |
| Copyright (C) 2007-2020 Free Software Foundation, Inc. |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| #include <config.h> |
| |
| /* Specification. */ |
| #include "fwritable.h" |
| |
| #include "stdio-impl.h" |
| |
| #if defined EPLAN9 /* Plan9 */ |
| # include <fcntl.h> |
| #endif |
| |
| /* This file is not used on systems that have the __fwritable function, |
| namely glibc >= 2.2, Solaris >= 7, Android API >= 23, musl libc. */ |
| |
| bool |
| fwritable (FILE *fp) |
| { |
| /* Most systems provide FILE as a struct and the necessary bitmask in |
| <stdio.h>, because they need it for implementing getc() and putc() as |
| fast macros. */ |
| #if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 |
| /* GNU libc, BeOS, Haiku, Linux libc5 */ |
| return (fp->_flags & _IO_NO_WRITES) == 0; |
| #elif defined __sferror || defined __DragonFly__ || defined __ANDROID__ |
| /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */ |
| return (fp_->_flags & (__SRW | __SWR)) != 0; |
| #elif defined __EMX__ /* emx+gcc */ |
| return (fp->_flags & (_IORW | _IOWRT)) != 0; |
| #elif defined __minix /* Minix */ |
| return (fp->_flags & _IOWRITE) != 0; |
| #elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw, MSVC, NonStop Kernel, OpenVMS */ |
| return (fp_->_flag & (_IORW | _IOWRT)) != 0; |
| #elif defined __QNX__ /* QNX */ |
| return (fp->_Mode & 0x2 /* _MOPENW */) != 0; |
| #elif defined __MINT__ /* Atari FreeMiNT */ |
| return fp->__mode.__write; |
| #elif defined EPLAN9 /* Plan9 */ |
| int fd = fp->fd; |
| if (fd >= 0) |
| { |
| int flags = fcntl (fd, F_GETFL, NULL); |
| if (flags >= 0) |
| { |
| flags &= O_ACCMODE; |
| return (flags == O_WRONLY || flags == O_RDWR); |
| } |
| } |
| return 0; |
| #else |
| # error "Please port gnulib fwritable.c to your platform! Look at the definition of fopen, fdopen on your system, then report this to bug-gnulib." |
| #endif |
| } |