1.管道
1.1普通管道
#include <unistd.h>
#include <sys/types.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
int main()
{
int pipe_fd[2];
pid_t pid;
char buf_r[100];
char *p_wbuf;
int r_num;
memset(buf_r, 0, sizeof(buf_r));
if(pipe(pipe_fd) < 0)
{
printf("pipe create error!/n");
return -1;
}
if((pid = fork()) == 0)
{
printf("/n");
close(pipe_fd[1]);
sleep(2);
if((r_num = read(pipe_fd[0], buf_r, 100)) > 0)
{
printf("%d numbers read from the pipe is %s/n", r_num, buf_r);
}
close(pipe_fd[0]);
exit(0);
}
else if(pid > 0)
{
close(pipe_fd[0]);
if(write(pipe_fd[1], "Hello", 5) != -1)
printf("parent write surcess/n");
if(write(pipe_fd[1], "pipe", 5) != -1)
printf("parent write success/n");
close(pipe_fd[1]);
sleep(2);
waitpid(pid, NULL, 0);
exit(0);
}
}
1.2 基于文件流管理
/*流管道*/
#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#define BUFSIZE 1024
int main()
{
FILE *fp;
char *cmd = "ps -ef";
char buf[BUFSIZE];
buf[BUFSIZE] = '/0';
if((fp = popen(cmd, "r")) == NULL)
perror("popen");
while((fgets(buf, BUFSIZE, fp)) != NULL)
printf("%s", buf);
pclose(fp);
exit(0);
}
1.3命名管道
读
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define FIFO "/tmp/myfifo"
int
main(int argc, char **argv)
{
char buf_r[100];
int fd;
int nread;
if((mkfifo(FIFO, O_CREAT | O_EXCL) < 0) && (errno != EEXIST))
printf("cannot create fifoserver/n");
printf("Preparing for reading bytes../n");
memset(buf_r, 0 , sizeof(buf_r));
fd = open(FIFO, O_RDONLY | O_NONBLOCK, 0);
if(fd == -1)
{
perror("open FIFO failed!/n");
exit(1);
}
while(1)
{
memset(buf_r, 0, sizeof(buf_r));
if((nread = read(fd, buf_r, 100)) == -1)
{
if(errno == EAGAIN)
printf("no data yet]n");
}
printf("read %s, from FIFO/n", buf_r);
sleep(1);
}
pause();
unlink(FIFO);
}
写
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define FIFO_SERVER "/tmp/myfifo"
int
main(int argc, char ** argv)
{
int fd;
char w_buf[100];
int nwrite;
fd = open(FIFO_SERVER, O_WRONLY | O_NONBLOCK, 0);
if(fd == -1)
{
if(errno == ENXIO)
printf("open error, no reading process/n");
}
if(argc == 1)
printf("Please send something/n");
strcpy(w_buf, argv[1]);
if((nwrite = write(fd, w_buf, 100)) == -1)
{
if(errno == EAGAIN)
printf("no data yet/n");
}
else
printf("write %d characters: %s/n", nwrite, w_buf);
}
信号及信号集
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
void my_func(int sig_no)
{
if(sig_no == SIGINT)
printf("I have get SIGINT/n");
else if(sig_no == SIGQUIT)
printf("I have get SIGQUIT/n");
}
int main()
{
printf("Waiting for signal SIGINT or SIGQUIT/n");
signal(SIGINT, my_func);
signal(SIGQUIT, my_func);
pause();
exit(0);
}
2. 信号集
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
void my_func(int signum)
{
printf("If you want to quit, please try SIGQUIT/n");
}
int main()
{
sigset_t set, pendset;
struct sigaction action1, action2;
if(sigemptyset(&set) < 0)
perror("sigemptyset");
if(sigaddset(&set, SIGQUIT) < 0)
perror("sigaddset");
if(sigaddset(&set, SIGINT) < 0)
perror("sigaddset");
if(sigprocmask(SIG_BLOCK, &set, NULL) < 0)
perror("sigprocmask");
else
{
printf("block/n");
sleep(5);
}
if(sigprocmask(SIG_UNBLOCK, &set, NULL) < 0)
perror("sigprocmask");
else
printf("unblock/n");
while(1)
{
if(sigismember(&set, SIGINT))
{
sigemptyset(&action1.sa_mask);
action1.sa_handler = my_func;
sigaction(SIGINT, &action1, NULL);
}
else if(sigismember(&set, SIGQUIT))
{
sigemptyset(&action2.sa_mask);
action2.sa_handler = SIG_DFL;
sigaction(SIGTERM, &action2, NULL);
}
}
}
3. 共享内存（大型数据传输）
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#define BUFSZ 2048
int main()
{
int shmid;
char *shmadd;
key_t key;
if((key = ftok(".", 'a')) == -1)
{
perror("ftok");
exit(1);
}
if((shmid = shmget(IPC_PRIVATE, BUFSZ, 0666)) < 0)
{
perror("shmget");
exit(1);
}
else
{
printf("created shared-memory: %d/n", shmid);
system("ipcs –m");
}
if((shmadd = shmat(shmid, 0, 0)) < (char*)0)
{
perror("shmat");
exit(1);
}
else
{
printf("attached shared-memory/n");
system("ipcs –m");
}
if(shmdt(shmadd) < 0)
{
perror("shmdt");
exit(1);
}
else
{
printf("dettached shared-memory/n");
system("ipcs -m");
}
exit(0);
}
4. 消息队列（少量数据传输）
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#define BUFSZ 512
struct message
{