Linux C Programming - Pipes

In Linux, a pipe is also a kind of file, but it is special. We can use the pipe function to create a pipe, and its prototype is declared as follows:

#inlcude

int pipe(int fields[2] );

In fact, it is equivalent to a communication buffer, fields[0] is used for reading, and fields[1] is used for writing. In the following example, a pipe is created as a communication buffer. The parent process creates a child process. The child process writes a string into the pipe through the fields[1] descriptor of the pipe, while the parent process uses the fields[1] of the pipe. 0] Read this string from the pipe and display it:

#include
#include
#include
#include #include
#include
#include

#define BUF_SIZ 255 // message buffer size

int main(int argc , char **argv)
{
char buffer[BUF_SIZ + 1];
int fd[2];

// receive a string as parameter
if (argc != 2)
{
fprintf (stderr, "Usage : %s stringna", argv[0]);
exit(1);
}

// create pipe for communication
if (pipe(fd) != 0)
{
fprintf(stderr, "C reate pipe error : %sna", strerror(errno));
exit(1);
}

if (fork() == 0) // in child process write msg to pipe
{
close(fd[0]); "Printf (" Child%LD WRITE to PIPENA ", Getpid ());
Snprintf (buffer, buf_siz,"%s ", argv [1]);
Write (fd [1], buffer, strlen (buffer)) ; T Printf ("Child%ld quit.na", getpid ());
}
else // in Parent Process, Read MSG from Pipe
{
Close (fd [1]); read from pipena", getpid());
memset(buffer, '