7.20.4.6 The system function
Synopsis
#include <stdlib.h>
int system(const char *string);
Description
If string is a null pointer, the system function determines whether the host environment has a command processor. If string is not a null pointer, the system function passes the string pointed to by string to that command processor to be executed in a manner which the implementation shall document; this might then cause the program calling system to behave in a non-conforming manner or to terminate.
Returns
If the argument is a null pointer, the system function returns nonzero only if a command processor is available. If the argument is not a null pointer, and the system function does return, it returns an implementation-defined value.