#include <stdlib.h>
int system(const char *command);
The system() function
passes the string pointed to by command to the host
environment so that a command processor can execute it. By
passing command as a NULL,
system() can inquire whether a command processor exists.
system() causes the
string to be given to the shell as input as if the string had
been typed as a command at a terminal. The current process waits
until the shell has completed then returns the exit status of the
shell in the format that waitpid() specifies.
system() ignores the SIGINT and
SIGQUIT signals, and blocks the SIGCHLD
signal while waiting for the command to terminate. If this might cause the
calling process to miss a signal that would have killed it, then the calling
process should examine the return value from system()
and take whatever action is appropriate to the application if the command
terminated due to receipt of a signal.
The system() function
will not affect the termination status of any child of the
calling processes other than the process or processes it itself creates.
The system() function does not return until the
child process has terminated.
- command
-
Points to the string that is passed to the host environment.
If command is a null pointer, system()
returns non-zero only if a command processor is available.
If command is not a null pointer, system()
returns the termination status of the command language interpreter in the
format specified by waitpid(). If some error prevents
the command language interpreter from executing after the child process is
created, the return value from system() is as if the
command language interpreter had terminated using exit(127)
or _exit(127). If a child process cannot be created,
or if the termination status for the command language interpreter
cannot be obtained, system() returns -1
and sets errno to indicate the error:
- ECHILD
-
Error with the child process
- EINVAL
-
Invalid command processor.
- ENOENT
-
No command processor found.
POSIX.1 (1996), with exceptions.
MT-Safe.
There is no default shell in the Window environment. Hence, the NuTCRACKER Platform first
checks for SHELL in the environment to determine the
shell to use, and then checks COMSPEC for a fall-back
command interpreter. If neither is set, then system() fails.
The NuTCRACKER Platform implements system() using
_NutForkExeclp(); refer to that function for more
information on how the command processor is invoked.
You must ensure that any path name arguments you pass to non-NuTCRACKER Platform
applications are in Win32 format, as only NuTCRACKER Platform applications
recognize the NuTCRACKER Platform format. Refer to Path Names
in the Windows Concepts chapter of the
PTC MKS Toolkit UNIX to Windows Porting Guide for more
information.
PTC MKS Toolkit for Professional Developers
PTC MKS Toolkit for Professional Developers 64-Bit Edition
PTC MKS Toolkit for Enterprise Developers
PTC MKS Toolkit for Enterprise Developers 64-Bit Edition
- Functions:
- _exit(), _NutForkExeclp(), exit(), pclose(), popen(), waitpid()
PTC MKS Toolkit 10.4 Documentation Build 39.