The srv_callback routine allows you to install a callback handler for a thread. Open Server calls your routine whenever the state of the thread changes to the state you specify. For example, you can install a SRV_C_SUSPEND callback handler that executes whenever the thread is suspended.
The ability to install and execute callback handlers
is platform-dependent. Use srv_capability to
find out if a callback handler can be installed for a particular
state transition on your current platform.
Table 2-23 summarizes the state transitions for which srv_callback can install callback handlers:
State transition |
Meaning |
|---|---|
SRV_C_EXIT |
The thread has finished executing the routine it was spawned to execute, or it is associated with a disconnected client. The handler executes in the context of the exiting thread. |
SRV_C_PROCEXEC |
Open Server calls this callback when a registered procedure is about to execute. The handler executes in the context of the thread that requested the registered procedure. As a result, the SRV_C_PROCEXEC callback handler executes whenever a client attempts any registered procedure operation. You can install a callback handler that restricts clients’ abilities to create, delete, or execute registered procedures. |
SRV_C_RESUME |
The thread is resuming. The handler executes in the context of the scheduler thread and uses the scheduler’s stack. |
SRV_C_SUSPEND |
The thread is suspending. The handler executes in the context of the thread that is suspending and uses its stack. |
SRV_C_TIMESLICE |
A thread has executed for a period of time (time slice) determined by the SRV_TIMESLICE, SRV_VIRTCLKRATE, and SRV_VIRTTIMER configuration parameters. You can use this handler to signal a long-running thread to call srv_yield so that other threads can run. |
