Guardian Procedure Calls Reference Manual

PROCESS_DELAY_ Procedure
Summary
Syntax for C Programmers
Syntax for TAL Programmers
Parameter
Considerations
Example
Summary
The PROCESS_DELAY_ procedure permits a process to suspend itself for a timed interval.
The PROCESS_DELAY_ procedure is supported only in J-series and H-series RVUs.
Syntax for C Programmers
#include <cextdecs(PROCESS_DELAY_)>
void PROCESS_DELAY_ ( long long timeout );
Syntax for TAL Programmers
CALL PROCESS_DELAY_ ( timeout ) ; ! i
Parameter
timeout
input
FIXED:value
specifies the time, in microsecond units, that the caller of PROCESS_DELAY_ is to be suspended.
Considerations
• The process stops executing for at least timeout microseconds. The actual delay is somewhat
longer than the specified value, because:
◦ The specified timeout is rounded up to the resolution of the operating system interval
timing mechanism, which is approximately 2 milliseconds.
◦ Once the interval timer has elapsed, there is variable latency to process the timer interrupt
and schedule the process by priority, and then the process must read the message.
• timeout value <= 0D
A value of less than or equal to 0D results in no delay as such, but returns this process to the
Ready List.
• Measuring time by the processor clock
The PROCESS_DELAY_ procedure measures time according to the internal clock of the processor
in which the calling process is executing. Processor time is time as measured by a particular
process. Typically, processor time differs slightly from system time and varies slightly from
processor to processor. System time is determined by taking the average of all the processor
times in the system.
When measuring short intervals, the difference between processor time and system time is
negligible. However, when measuring long intervals (such as several hours or more), the
PROCESS_DELAY_ Procedure 1003