system

int system (const char* command);

Execute system command

Invokes the command processor to execute a command.

If command is a null pointer, the function only checks whether a command processor is available through this function, without invoking any command.

The effects of invoking a command depend on the system and library implementation, and may cause a program to behave in a non-standard manner or to terminate.

Parameters

command: C-string containing the system command to be executed.
Or, alternatively, a null pointer, to check for a command processor.

Return Value

If command is a null pointer, the function returns a non-zero value in case a command processor is available and a zero value if it is not.

If command is not a null pointer, the value returned depends on the system and library implementations, but it is generally expected to be the status code returned by the called command, if supported.

Example

/* system example : DIR */ #include <stdio.h> /* printf */ #include <stdlib.h> /* system, NULL, EXIT_FAILURE */ int main () { int i; printf ("Checking if processor is available..."); if (system(NULL)) puts ("Ok"); else exit (EXIT_FAILURE); printf ("Executing command DIR...\n"); i=system ("dir"); printf ("The value returned was: %d.\n",i); return 0; }

Data races

The function accesses the array pointed by command.
Concurrently calling this function with a null pointer as argument is safe. Otherwise, it depends on the system and library implementation.

Exceptions (C++)

No-throw guarantee: this function does not throw exceptions.

If command is not a null pointer, it causes undefined behavior.

functions

functions (non-standard)

types