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@cou929
Created January 29, 2012 02:22
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test of O_NONBLOCK from APUE Chapter 12
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
void set_fl(int fd, int flags);
void clr_fl(int fd, int flags);
char buf[100000];
int main(void) {
int ntowrite, nwrite;
char *ptr;
ntowrite = read(STDIN_FILENO, buf, sizeof(buf));
fprintf(stderr, "read %d byts\n", ntowrite);
set_fl(STDOUT_FILENO, O_NONBLOCK);
for (ptr = buf; ntowrite > 0; ) {
errno = 0;
nwrite = write(STDOUT_FILENO, ptr, ntowrite);
fprintf(stderr, "nwrite = %d, errno = %d, err_message = '%s'\n", nwrite, errno, strerror(errno));
if (nwrite > 0) {
ptr += nwrite;
ntowrite -= nwrite;
}
}
clr_fl(STDOUT_FILENO, O_NONBLOCK);
return 0;
}
void set_fl(int fd, int flags) {
int val;
if ((val = fcntl(fd, F_GETFL, 0)) < 0) {
fprintf(stderr, "fcntl F_GETFL error");
exit(1);
}
val |= flags; /* turn on flags */
if (fcntl(fd, F_SETFL, val) < 0) {
fprintf(stderr, "fcntl F_SETFL error");
exit(1);
}
}
void clr_fl(int fd, int flags) {
int val;
if ((val = fcntl(fd, F_GETFL, 0)) < 0) {
fprintf(stderr, "fcntl F_GETFL error");
exit(1);
}
val &= ~flags; /* turn flags off */
if (fcntl(fd, F_SETFL, val) < 0) {
fprintf(stderr, "fcntl F_SETFL error");
exit(1);
}
}
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