Execute command.
  Invokes command interpreter to execute a command. Once terminated, the interpreter gives back control to the program returning an int value.

Parameters.

command

Null-terminated string containing the system command to be executed.

Return Value.
  If a command was successfully executed the command interpreter returns an adequate value; generally 0 indicates that the action performed by the command interpreter terminated with no errors.
  A return value of -1 indicates an error, and global variable errno is set to one of the following errors:

value	description
ENOENT	Command interpreter not found
ENOEXEC	Command interpreter is not executable
ENOMEM	Error allocating memory for the process
E2BIG	Argument list too big

Portability.
  Defined in ANSI-C.
  Return value and possible errno values are system dependent.

Example.

/* system example : DIR */
#include <stdio.h>
#include <stdlib.h>

main ()
{
  int i;
  puts ("Trying to execute command DIR");
  i = system ("dir");
  if (i==-1) puts ("Error executing DIR");
  else puts ("Command successfully executed");
  return 0;
}

See also.
  atof, strtol, strtoul