writen.c

/* include writen */
#include "unp.h"

ssize_t /* Write "n" bytes to a descriptor. */
writen(int fd, const void *vptr, size_t n)
{
size_t nleft;
ssize_t nwritten;
const char *ptr;

ptr = vptr;
nleft = n;
while (nleft > 0) {
if ( (nwritten = write(fd, ptr, nleft)) <= 0) {
if (errno == EINTR)
nwritten = 0; /* and call write() again */
else
return(-1); /* error */
}

nleft -= nwritten;
ptr   += nwritten;
}
return(n);
}
/* end writen */

void
Writen(int fd, void *ptr, size_t nbytes)
{
if (writen(fd, ptr, nbytes) != nbytes)
err_sys("writen error");
}