Function drmgr_register_post_syscall_event 

pub unsafe extern "C" fn drmgr_register_post_syscall_event(
    func: Option<unsafe extern "C" fn(drcontext: *mut c_void, sysnum: c_int)>,
) -> bool_

Registers a callback function for the post-syscall event, which behaves just like DR’s post-syscall event dr_register_post_syscall_event(). \return whether successful.