kc3-lang/gnulib/lib/full-write.c

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• Hash : 57fdfd3f
  Author :
  Date : 2007-10-07T19:14:58
  

  Change copyright notice from GPLv2+ to GPLv3+.
  

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• lib/full-write.c

• /* An interface to read and write that retries (if necessary) until complete.
  
     Copyright (C) 1993, 1994, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
     2004, 2005, 2006 Free Software Foundation, Inc.
  
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  #include <config.h>
  
  /* Specification.  */
  #ifdef FULL_READ
  # include "full-read.h"
  #else
  # include "full-write.h"
  #endif
  
  #include <errno.h>
  
  #ifdef FULL_READ
  # include "safe-read.h"
  # define safe_rw safe_read
  # define full_rw full_read
  # undef const
  # define const /* empty */
  #else
  # include "safe-write.h"
  # define safe_rw safe_write
  # define full_rw full_write
  #endif
  
  #ifdef FULL_READ
  /* Set errno to zero upon EOF.  */
  # define ZERO_BYTE_TRANSFER_ERRNO 0
  #else
  /* Some buggy drivers return 0 when one tries to write beyond
     a device's end.  (Example: Linux 1.2.13 on /dev/fd0.)
     Set errno to ENOSPC so they get a sensible diagnostic.  */
  # define ZERO_BYTE_TRANSFER_ERRNO ENOSPC
  #endif
  
  /* Write(read) COUNT bytes at BUF to(from) descriptor FD, retrying if
     interrupted or if a partial write(read) occurs.  Return the number
     of bytes transferred.
     When writing, set errno if fewer than COUNT bytes are written.
     When reading, if fewer than COUNT bytes are read, you must examine
     errno to distinguish failure from EOF (errno == 0).  */
  size_t
  full_rw (int fd, const void *buf, size_t count)
  {
    size_t total = 0;
    const char *ptr = (const char *) buf;
  
    while (count > 0)
      {
        size_t n_rw = safe_rw (fd, ptr, count);
        if (n_rw == (size_t) -1)
  	break;
        if (n_rw == 0)
  	{
  	  errno = ZERO_BYTE_TRANSFER_ERRNO;
  	  break;
  	}
        total += n_rw;
        ptr += n_rw;
        count -= n_rw;
      }
  
    return total;
  }
  

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