The mi_system() function
The mi_system() function allows you to execute operating system commands from within a DataBlade® module or C UDR.
Syntax
mi_integer mi_system(const mi_char *cmd);
- cmd
- An operating system command, surrounded by quotation marks.
Valid in client LIBMI application? | Valid in user-defined routine? |
---|---|
Yes | Yes |
Usage
Use the mi_system() function from within a DataBlade® module or C UDR to execute operating system commands, external user executables, or shell scripts. The mi_system() function creates a child process to execute the command, waits for its completion, and then returns the command's exit status to the calling routine. The child process inherits the user and group IDs of the client running the session.
The mi_system() function does not perform any validation on the command you run, therefore, you must take care to run appropriate and accurate commands. For information about good coding practices within user-defined routines, see the Informix® DataBlade® API Programmer's Guide.
ret = mi_system(rm /tmp/lo*);
check_retval(ret); /* Check exit status */
mi_system("/p1/p2/myexe param1 param2")
or
mi_system("sh /p1/p2/myscript.sh")
The mi_system() function treats the first string within the quotation marks as the command and the following strings as parameters passed to the command.
mi_system("echo 'Check this out' >> /tmp/myfile")
because mi_system() treats echo
as
the command to be run and 'Check this out', >>,
and /tmp/myfile
as
its parameters. To successfully run these commands, create a shell
script, such as mysh.sh
, which contains the following
lines: #!/bin/sh
echo 'Check this out' >> /tmp/myfile
mi_system("sh /p1/p2/mysh.sh")
For more information about executing operating system commands, see the Informix® DataBlade® API Programmer's Guide.
Return values
- An integer
- The success, failure, or error code returned by the operating system command.
- MI_ERROR
- The operating system command cannot be executed.