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SYSTEM(3) Library Functions Manual SYSTEM(3)


systempass a command to the shell


#include <stdlib.h>
system(const char *string);


The system() function hands the argument string to the command interpreter sh(1). The calling process waits for the shell to finish executing the command, ignoring SIGINT and SIGQUIT, and blocking SIGCHLD.
If string is NULL, system() will return non-zero. Otherwise, system() returns the termination status of the shell in the format specified by waitpid(2).
Note that fork handlers established using pthread_atfork(3) are not called when a multithreaded program calls system().


If a child process cannot be created, or the termination status of the shell cannot be obtained, system() returns -1 and sets errno to indicate the error. If execution of the shell fails, system() returns the termination status for a program that terminates with a call of exit(127).


sh(1), execve(2), waitpid(2), popen(3)


The system() function conforms to ANSI X3.159-1989 (“ANSI C89”) and IEEE Std 1003.2-1992 (“POSIX.2”).


The system() function first appeared in Version 6 AT&T UNIX.


Never supply the system() function with a command containing any part of an unsanitized user-supplied string. Shell meta-characters present will be honored by the sh(1) command interpreter.
It is often simpler to bypass the shell and run an external command using fork(2), execlp(3), and waitpid(2) directly instead of having to sanitize a string for shell consumption.
February 5, 2016 OpenBSD-current