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#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>
#include <unistd.h>
#include <getopt.h>
#include <errno.h>
/* pipe file descriptors */
static int fd[2];
/* send/write size */
static size_t size;
/* options */
static struct option long_opts[] = {
{ "size", required_argument, NULL, 's' },
{ NULL, 0, NULL, 0 },
};
static void *reader(void *arg)
{
unsigned char buf[size];
ssize_t read_ = 0;
while (read_ < size) {
ssize_t ret;
ret = read(fd[0], buf + read_, size - read_);
if (ret < 0) {
perror("read() failed");
exit(EXIT_FAILURE);
}
read_ += ret;
}
printf("Reader: got data\n");
return NULL;
}
static void *writer(void *arg)
{
unsigned char buf[size];
ssize_t written = 0;
sleep(1);
while (written < size) {
ssize_t ret;
ret = write(fd[1], buf + written, size - written);
if (ret < 0) {
perror("write() failed");
exit(EXIT_FAILURE);
}
written += ret;
}
printf("Writer: sent data\n");
sleep(1);
return NULL;
}
static inline void print_usage_and_die(void)
{
fprintf(stderr, "usage: pipedemo [-s <size>]\n");
exit(EXIT_FAILURE);
}
int main(int argc, char **argv)
{
pthread_t tid1, tid2;
char *end;
int c;
size = 4 << 10;
while ((c = getopt_long(argc, argv, "s:", long_opts, NULL)) != -1) {
switch (c) {
case 's':
size = strtoull(optarg, &end, 10);
if (end == optarg || *end != '\0' || errno == ERANGE) {
fprintf(stderr, "given size is not valid\n");
return EXIT_FAILURE;
}
break;
default:
print_usage_and_die();
}
}
if (pipe(fd) < 0) {
perror("pipe() failed");
return EXIT_FAILURE;
}
if (pthread_create(&tid1, NULL, reader, NULL) ||
pthread_create(&tid2, NULL, writer, NULL)) {
fprintf(stderr, "pthread_create() failed\n");
return EXIT_FAILURE;
}
if (pthread_setname_np(tid1, "pipedemo-reader") ||
pthread_setname_np(tid2, "pipedemo-writer")) {
fprintf(stderr, "pthread_create() failed\n");
return EXIT_FAILURE;
}
pthread_join(tid1, NULL);
pthread_join(tid2, NULL);
return EXIT_SUCCESS;
}
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