1: /* Copyright (C) 1993, 1995, 1996, 1997, 1998, 1999, 2002, 2003, 2005
    2:    Free Software Foundation, Inc.
    3:    This file is part of the GNU C Library.
    4: 
    5:    The GNU C Library is free software; you can redistribute it and/or
    6:    modify it under the terms of the GNU Lesser General Public
    7:    License as published by the Free Software Foundation; either
    8:    version 2.1 of the License, or (at your option) any later version.
    9: 
   10:    The GNU C Library is distributed in the hope that it will be useful,
   11:    but WITHOUT ANY WARRANTY; without even the implied warranty of
   12:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   13:    Lesser General Public License for more details.
   14: 
   15:    You should have received a copy of the GNU Lesser General Public
   16:    License along with the GNU C Library; if not, write to the Free
   17:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   18:    02111-1307 USA.
   19: 
   20:    As a special exception, if you link the code in this file with
   21:    files compiled with a GNU compiler to produce an executable,
   22:    that does not cause the resulting executable to be covered by
   23:    the GNU Lesser General Public License.  This exception does not
   24:    however invalidate any other reasons why the executable file
   25:    might be covered by the GNU Lesser General Public License.
   26:    This exception applies to code released by its copyright holders
   27:    in files containing the exception.  */
   28: 
   29: #include "libioP.h"
   30: #include <stdio.h>
   31: 
   32: char *
   33: _IO_fgets (buf, n, fp)
   34:      char *buf;
   35:      int n;
   36:      _IO_FILE *fp;
   37: {
   38:   _IO_size_t count;
   39:   char *result;
   40:   int old_error;
   41:   CHECK_FILE (fp, NULL);
   42:   if (n <= 0)
   43:     return NULL;
   44:   if (__builtin_expect (n == 1, 0))
   45:     {
   46:       /* Another irregular case: since we have to store a NUL byte and
   47:          there is only room for exactly one byte, we don't have to
   48:          read anything.  */
   49:       buf[0] = '\0';
   50:       return buf;
   51:     }
   52:   _IO_acquire_lock (fp);
   53:   /* This is very tricky since a file descriptor may be in the
   54:      non-blocking mode. The error flag doesn't mean much in this
   55:      case. We return an error only when there is a new error. */
   56:   old_error = fp->_IO_file_flags & _IO_ERR_SEEN;
   57:   fp->_IO_file_flags &= ~_IO_ERR_SEEN;
   58:   count = INTUSE(_IO_getline) (fp, buf, n - 1, '\n', 1);
   59:   /* If we read in some bytes and errno is EAGAIN, that error will
   60:      be reported for next read. */
   61:   if (count == 0 || ((fp->_IO_file_flags & _IO_ERR_SEEN)
   62:                      && errno != EAGAIN))
   63:     result = NULL;
   64:   else
   65:     {
   66:       buf[count] = '\0';
   67:       result = buf;
   68:     }
   69:   fp->_IO_file_flags |= old_error;
   70:   _IO_release_lock (fp);
   71:   return result;
   72: }
   73: 
   74: #ifdef weak_alias
   75: weak_alias (_IO_fgets, fgets)
   76: 
   77: # ifndef _IO_MTSAFE_IO
   78: weak_alias (_IO_fgets, fgets_unlocked)
   79: libc_hidden_weak (fgets_unlocked)
   80: # endif
   81: #endif