* @cmd...: NULL-terminate list of command and arguments.
*
* If @infd is NULL, the child's input is (read-only) /dev/null.
* If @outfd is NULL, the child's output is (write-only) /dev/null.
* @cmd...: NULL-terminate list of command and arguments.
*
* If @infd is NULL, the child's input is (read-only) /dev/null.
* If @outfd is NULL, the child's output is (write-only) /dev/null.