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[glibc.git] / libio / iogets.c
blobb36d29ba6ce0abb196731a505f613d896ab4ce37
1 /* Copyright (C) 1993, 1996, 1997, 1998 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 #include "libioP.h"
27 #include <limits.h>
29 char*
30 _IO_gets (buf)
31 char *buf;
33 _IO_size_t count;
34 int ch;
35 char *retval;
37 _IO_cleanup_region_start ((void (*) __P ((void *))) _IO_funlockfile,
38 _IO_stdin);
39 _IO_flockfile (_IO_stdin);
40 ch = _IO_getc_unlocked (_IO_stdin);
41 if (ch == EOF)
43 retval = NULL;
44 goto unlock_return;
46 if (ch == '\n')
47 count = 0;
48 else
50 /* This is very tricky since a file descriptor may be in the
51 non-blocking mode. The error flag doesn't mean much in this
52 case. We return an error only when there is a new error. */
53 int old_error = _IO_stdin->_IO_file_flags & _IO_ERR_SEEN;
54 _IO_stdin->_IO_file_flags &= ~_IO_ERR_SEEN;
55 buf[0] = (char) ch;
56 count = _IO_getline (_IO_stdin, buf + 1, INT_MAX, '\n', 0) + 1;
57 if (_IO_stdin->_IO_file_flags & _IO_ERR_SEEN)
59 retval = NULL;
60 goto unlock_return;
62 else
63 _IO_stdin->_IO_file_flags |= old_error;
65 buf[count] = 0;
66 retval = buf;
67 unlock_return:
68 _IO_funlockfile (_IO_stdin);
69 _IO_cleanup_region_end (0);
70 return retval;
73 #ifdef weak_alias
74 weak_alias (_IO_gets, gets)
75 #endif
77 #ifdef _LIBC
78 link_warning (gets, "the `gets' function is dangerous and should not be used.")
79 #endif