1: /* Copyright (C) 1993,1996,1997,1998,2002,2003 Free Software Foundation, Inc.
    2:    This file is part of the GNU C Library.
    3: 
    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.
    8: 
    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.
   13: 
   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.
   18: 
   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.  */
   27: 
   28: #include "libioP.h"
   29: #include <limits.h>
   30: 
   31: char*
   32: _IO_gets (buf)
   33:      char *buf;
   34: {
   35:   _IO_size_t count;
   36:   int ch;
   37:   char *retval;
   38: 
   39:   _IO_acquire_lock (_IO_stdin);
   40:   ch = _IO_getc_unlocked (_IO_stdin);
   41:   if (ch == EOF)
   42:     {
   43:       retval = NULL;
   44:       goto unlock_return;
   45:     }
   46:   if (ch == '\n')
   47:     count = 0;
   48:   else
   49:     {
   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 = INTUSE(_IO_getline) (_IO_stdin, buf + 1, INT_MAX, '\n', 0) + 1;
   57:       if (_IO_stdin->_IO_file_flags & _IO_ERR_SEEN)
   58:         {
   59:           retval = NULL;
   60:           goto unlock_return;
   61:         }
   62:       else
   63:         _IO_stdin->_IO_file_flags |= old_error;
   64:     }
   65:   buf[count] = 0;
   66:   retval = buf;
   67: unlock_return:
   68:   _IO_release_lock (_IO_stdin);
   69:   return retval;
   70: }
   71: 
   72: #ifdef weak_alias
   73: weak_alias (_IO_gets, gets)
   74: #endif
   75: 
   76: #ifdef _LIBC
   77: link_warning (gets, "the `gets' function is dangerous and should not be used.")
   78: #endif