os161-1.99
 All Data Structures
conman.c
00001 /*
00002  * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
00003  *      The President and Fellows of Harvard College.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  * 1. Redistributions of source code must retain the above copyright
00009  *    notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *    notice, this list of conditions and the following disclaimer in the
00012  *    documentation and/or other materials provided with the distribution.
00013  * 3. Neither the name of the University nor the names of its contributors
00014  *    may be used to endorse or promote products derived from this software
00015  *    without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
00018  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED.  IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
00021  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00022  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00023  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00024  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00025  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00026  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00027  * SUCH DAMAGE.
00028  */
00029 
00030 /*
00031  * conman.c
00032  *
00033  * Echoes characters until a 'q' is read.
00034  * This should work once the basic system calls are implemented.
00035  */
00036 
00037 #include <unistd.h>
00038 #include <err.h>
00039 
00040 int
00041 main() {
00042         char ch=0;
00043         int len;
00044 
00045         while (ch!='q') {
00046                 len = read(STDIN_FILENO, &ch, 1);
00047                 if (len < 0) {
00048                         err(1, "stdin: read");
00049                 }
00050                 if (len==0) {
00051                         /* EOF */
00052                         break;
00053                 }
00054                 write(STDOUT_FILENO, &ch, 1);
00055         }
00056         return 0;
00057 }
 All Data Structures