Interprocess communication using pipe in Linux

问题

I have written my code for writing a number to pipe in linux. it is as under,but it is showing errors,can anyone help me on this.

Basically the problem statement for the program is as below:- One program will open a pipe, write a number to pipe. - Other program will open the same pipe, will read the number and print them. - Close both the pipes

int main()
{

int number;




FILE *fout;

fout = popen("  ","w");



pclose(fout);

return 0;

}

Now my question is what command should i give in the popen command option (as shown blank above) so as i can proceed further and write a number to pipe.

回答1:

First, create a named pipe using the mknod command. mknod pipe p. Then read and write using functions as if they are files. A node can be created using code also, using the mknod function. Look for error code EEXIST. More information here. http://linux.die.net/man/2/mknod

回答2:

You don't understand well how IPC and pipes work; please read a good book: Advanced Linux Programming has several chapters on these issues.

^{We don't have hours to explain difficult concepts covered by such good books. Take several hours to read them!}

The library function popen(3) runs a command. Very probably, you don't have a p command on your system. I guess fp is NULL and errno is set.

popen is using pipe(2), fork(2), dup2(2), execve(2) and /bin/sh -c etc

来源：https://stackoverflow.com/questions/18159051/interprocess-communication-using-pipe-in-linux