* cp-tree.def (EMPTY_CLASS_EXPR): New tree node.
[official-gcc.git] / libio / iofdopen.c
blob841e7032b803218d1ed94896755146dea4eb8628
1 /* Copyright (C) 1993, 1994, 1997 Free Software Foundation, Inc.
2 This file is part of the GNU IO Library.
4 This library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU General Public License as
6 published by the Free Software Foundation; either version 2, or (at
7 your option) any later version.
9 This library is distributed in the hope that it will be useful, but
10 WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this library; see the file COPYING. If not, write to
16 the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
17 MA 02111-1307, USA.
19 As a special exception, if you link this library with files
20 compiled with a GNU compiler to produce an executable, this does
21 not cause the resulting executable to be covered by the GNU General
22 Public License. This exception does not however invalidate any
23 other reasons why the executable file might be covered by the GNU
24 General Public License. */
26 #ifdef __STDC__
27 #include <stdlib.h>
28 #endif
29 #include "libioP.h"
30 #include <fcntl.h>
32 #ifndef _IO_fcntl
33 #define _IO_fcntl fcntl
34 #endif
36 _IO_FILE *
37 _IO_fdopen (fd, mode)
38 int fd;
39 const char *mode;
41 int read_write;
42 int posix_mode = 0;
43 struct locked_FILE
45 struct _IO_FILE_plus fp;
46 #ifdef _IO_MTSAFE_IO
47 _IO_lock_t lock;
48 #endif
49 } *new_f;
50 int fd_flags;
52 switch (*mode++)
54 case 'r':
55 read_write = _IO_NO_WRITES;
56 break;
57 case 'w':
58 read_write = _IO_NO_READS;
59 break;
60 case 'a':
61 posix_mode = O_APPEND;
62 read_write = _IO_NO_READS|_IO_IS_APPENDING;
63 break;
64 default:
65 MAYBE_SET_EINVAL;
66 return NULL;
68 if (mode[0] == '+' || (mode[0] == 'b' && mode[1] == '+'))
69 read_write &= _IO_IS_APPENDING;
70 #ifdef F_GETFL
71 fd_flags = _IO_fcntl (fd, F_GETFL);
72 #ifndef O_ACCMODE
73 #define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
74 #endif
75 if (fd_flags == -1
76 || ((fd_flags & O_ACCMODE) == O_RDONLY && !(read_write & _IO_NO_WRITES))
77 || ((fd_flags & O_ACCMODE) == O_WRONLY && !(read_write & _IO_NO_READS)))
78 return NULL;
80 /* The May 93 draft of P1003.4/D14.1 (redesignated as 1003.1b)
81 [System Application Program Interface (API) Amendment 1:
82 Realtime Extensions], Rationale B.8.3.3
83 Open a Stream on a File Descriptor says:
85 Although not explicitly required by POSIX.1, a good
86 implementation of append ("a") mode would cause the
87 O_APPEND flag to be set.
89 (Historical implementations [such as Solaris2] do a one-time
90 seek in fdopen.)
92 However, we do not turn O_APPEND off if the mode is "w" (even
93 though that would seem consistent) because that would be more
94 likely to break historical programs.
96 if ((posix_mode & O_APPEND) && !(fd_flags & O_APPEND))
98 #ifdef F_SETFL
99 if (_IO_fcntl (fd, F_SETFL, fd_flags | O_APPEND) == -1)
100 #endif
101 return NULL;
103 #endif
105 new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
106 if (new_f == NULL)
107 return NULL;
108 #ifdef _IO_MTSAFE_IO
109 new_f->fp.file._lock = &new_f->lock;
110 #endif
111 _IO_init (&new_f->fp.file, 0);
112 _IO_JUMPS (&new_f->fp.file) = &_IO_file_jumps;
113 _IO_file_init (&new_f->fp.file);
114 #if !_IO_UNIFIED_JUMPTABLES
115 new_f->fp.vtable = NULL;
116 #endif
117 if (_IO_file_attach (&new_f->fp.file, fd) == NULL)
119 _IO_un_link (&new_f->fp.file);
120 free (new_f);
121 return NULL;
123 new_f->fp.file._flags &= ~_IO_DELETE_DONT_CLOSE;
125 new_f->fp.file._IO_file_flags =
126 _IO_mask_flags (&new_f->fp.file, read_write,
127 _IO_NO_READS+_IO_NO_WRITES+_IO_IS_APPENDING);
129 return (_IO_FILE *) &new_f->fp;
132 #ifdef weak_alias
133 weak_alias (_IO_fdopen, fdopen)
134 #endif