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[glibc/history.git] / libio / iofgets_u.c
blob4fb5b1c0fd5d3b0b5f9063c73efedf1bf5704cec
1 /* Copyright (C) 1993,1995-1998,2002,2005 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA.
19 As a special exception, if you link the code in this file with
20 files compiled with a GNU compiler to produce an executable,
21 that does not cause the resulting executable to be covered by
22 the GNU Lesser General Public License. This exception does not
23 however invalidate any other reasons why the executable file
24 might be covered by the GNU Lesser General Public License.
25 This exception applies to code released by its copyright holders
26 in files containing the exception. */
28 #include "libioP.h"
29 #include <stdio.h>
31 char *
32 fgets_unlocked (buf, n, fp)
33 char *buf;
34 int n;
35 _IO_FILE *fp;
37 _IO_size_t count;
38 char *result;
39 int old_error;
40 CHECK_FILE (fp, NULL);
41 if (n <= 0)
42 return NULL;
43 if (__builtin_expect (n == 1, 0))
45 /* Another irregular case: since we have to store a NUL byte and
46 there is only room for exactly one byte, we don't have to
47 read anything. */
48 buf[0] = '\0';
49 return buf;
51 /* This is very tricky since a file descriptor may be in the
52 non-blocking mode. The error flag doesn't mean much in this
53 case. We return an error only when there is a new error. */
54 old_error = fp->_IO_file_flags & _IO_ERR_SEEN;
55 fp->_IO_file_flags &= ~_IO_ERR_SEEN;
56 count = INTUSE(_IO_getline) (fp, buf, n - 1, '\n', 1);
57 /* If we read in some bytes and errno is EAGAIN, that error will
58 be reported for next read. */
59 if (count == 0 || ((fp->_IO_file_flags & _IO_ERR_SEEN)
60 && errno != EAGAIN))
61 result = NULL;
62 else
64 buf[count] = '\0';
65 result = buf;
67 fp->_IO_file_flags |= old_error;
68 return result;
70 libc_hidden_def (fgets_unlocked)