write.c (1223B)
1 /* -*-comment-start: "//";comment-end:""-*- 2 * GNU Mes --- Maxwell Equations of Software 3 * Copyright © 2016,2017,2018,2019 Jan (janneke) Nieuwenhuizen <janneke@gnu.org> 4 * 5 * This file is part of GNU Mes. 6 * 7 * GNU Mes is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 3 of the License, or (at 10 * your option) any later version. 11 * 12 * GNU Mes is distributed in the hope that it will be useful, but 13 * WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with GNU Mes. If not, see <http://www.gnu.org/licenses/>. 19 */ 20 21 #include <mes/lib.h> 22 #include <errno.h> 23 #include <stdio.h> 24 #include <unistd.h> 25 26 ssize_t 27 write (int filedes, void const *buffer, size_t size) 28 { 29 size_t skip = __buffered_read_clear (filedes); 30 if (skip) 31 lseek (filedes, -skip, SEEK_CUR); 32 int r = _write (filedes, buffer, size); 33 if (r < 0) 34 { 35 errno = -r; 36 r = -1; 37 } 38 else 39 errno = 0; 40 return r; 41 }