Set the real group ID of the current process. This is a privileged function and you need appropriate privileges (usually root) on your system to be able to perform this function. The appropriate order of function calls is posix_setgid() first, posix_setuid() last.
Note: If the caller is a super user, this will also set your effective group id
Example 1. posix_setgid() example
This example will print out your effective group id, once you change it.
|posix_getgrgid() for information on how to convert this into a useable group name|
|posix_getgid() get real group id.|