srv_setpri

Modify the scheduling priority of a thread.

CS_RETCODE srv_setpri(spp, mode, priority_value)

SRV_PROC        *spp;
CS_INT               mode;
CS_INT             priority_value;

mode: SRV_C_DELTAPRI, if priority_value is to adjust the current priority, or SRV_C_NEWPRI, if priority_value is the new priority.

priority_value: If mode is SRV_C_NEWPRI, priority_value is the new priority for the thread. If mode is SRV_C_DELTAPRI, a negative priority_value reduces the current priority by its absolute value and a positive priority_value increases the current priority.

**Table 3-128: Return values (srv_setpri)**
Returns	To indicate
CS_SUCCEED	The routine completed successfully.
CS_FAIL	The routine failed.

#include    <ospublic.h>

/*

** Local Prototype.

*/

CS_RETCODE       ex_srv_setpri PROTOTYPE((

SRV_PROC         *spp,

CS_INT           mode,

CS_INT           priority

));

/*

** EX_SRV_SETPRI

**

**    Example routine to change a thread’s scheduling priority.

**

** Arguments:

**  spp        A pointer to an internal thread control structure.

**  mode       Indicates whether a priority is relative or

 **              absolute.

**  priority   The change in priority value or the nrew

                 priority value.

**

** Returns:

**

**    CS_SUCCEED

**    CS_FAIL

*/

CS_RETCODE    ex_srv_setpri(spp, mode, priority)

SRV_PROC      *spp;

CS_INT        mode;

CS_INT        priority;

    return(srv_setpri(spp, mode, priority));

When a thread is started as the result of a client logging into the Open Server or as the result of a call to srv_createproc or srv_spawn, it has a priority of SRV_C_DEFAULTPRI.
srv_setpri can change the priority by specifying the new value or by adjusting the current value up or down by a specified value.
If a thread sets the priority of another thread to a level higher than its own, the other thread is scheduled to run immediately. Otherwise, the new priority of the affected thread takes effect the next time the scheduler runs.
If a thread that never sleeps has a priority higher than other threads, the lower priority threads will never have a chance to execute.
Internal Open Server threads run with a priority of SRV_C_DEFAULTPRI. If you raise the priority of a thread above SRV_C_DEFAULTPRI, it must sleep occasionally to allow these internal processes to run.
It is an error to reduce the priority to less than SRV_C_LOWPRIORITY or to increase it to a value greater than SRV_C_MAXPRIORITY.
srv_setpri cannot be used in a SRV_START handler.