The sched_getparam() function returns
the scheduling parameters of a process specified by pid in the sched_param structure pointed to by param.
If a process specified by pid exists and if the calling process has permission, the scheduling parameters for the process whose process ID is equal to pid will be returned.
If pid is 0, the scheduling parameters for the calling process will be returned. The behavior of the sched_getparam() function is unspecified if the value of pid is negative.