00001 /*
00002     writeall and readall
00003     AUP2, Sec. 2.09, 2.10
00004 
00005     Copyright 2003 by Marc J. Rochkind. All rights reserved.
00006     May be copied only for purposes and under conditions described
00007     on the Web page www.basepath.com/aup/copyright.htm.
00008 
00009     The Example Files are provided "as is," without any warranty;
00010     without even the implied warranty of merchantability or fitness
00011     for a particular purpose. The author and his publisher are not
00012     responsible for any damages, direct or incidental, resulting
00013     from the use or non-use of these Example Files.
00014 
00015     The Example Files may contain defects, and some contain deliberate
00016     coding mistakes that were included for educational reasons.
00017     You are responsible for determining if and how the Example Files
00018     are to be used.
00019 
00020 */
00021 #include "defs.h"
00022 
00023 /*
00024     Supposed to be a substitute for write(), so doesn't use ec.
00025     Unlike write(), can return -1 and also complete one or more
00026     partial writes.
00027 */
00028 /*[writeall]*/
00029 ssize_t writeall(int fd, const void *buf, size_t nbyte)
00030 {
00031     ssize_t nwritten = 0, n;
00032 
00033     do {
00034         if ((n = write(fd, &((const char *)buf)[nwritten],
00035           nbyte - nwritten)) == -1) {
00036             if (errno == EINTR)
00037                 continue;
00038             else
00039                 return -1;
00040         }
00041         nwritten += n;
00042     } while (nwritten < nbyte);
00043     return nwritten;
00044 }
00045 /*[readall]*/
00046 ssize_t readall(int fd, void *buf, size_t nbyte)
00047 {
00048     ssize_t nread = 0, n;
00049 
00050     do {
00051         if ((n = read(fd, &((char *)buf)[nread], nbyte - nread)) == -1) {
00052             if (errno == EINTR)
00053                 continue;
00054             else
00055                 return -1;
00056         }
00057         if (n == 0)
00058             return nread;
00059         nread += n;
00060     } while (nread < nbyte);
00061     return nread;
00062 }
00063 /*[]*/
c2/extio.c
