The system and popen functions in the standard C library provides an easy way to execute a command from within a program, much as if the command had been typed into a shell.
For lazy programmers, the system and popen functions exist. These functions must not be used in any security sensitive program.
These functions fork and then exec the user's login shell that locates the command and parses its arguments.
They use one of the wait family of functions to wait for the child process to terminate.
The popen function is similar to system, except it also calls pipe and creates a pipe to the standard input or from the standard output of the program, but not both.
#include <stdlib.h>
int main ()
{
int return_value;
return_value = system ("ls -l /");
return return_value;
}
The system function returns the exit status of the shell command. If the shell itself cannot be run, system returns 127; if another error occurs, system returns -1.
Because the system function uses a shell to invoke your command, it's subject to the features, limitations, and security flaws of the system's shell.
