User and Reference Guide

Contents

VT_countsetcallback

int VT_countsetcallback( VT_CountCallback_t callback, void *custom, int ncounters )
Description
Sets a callback for counter sampling for the calling thread.
The data provided by the callback is logged with the same time stamp as the event that triggered the callback. The callback must be set for each thread individually. Setting
NULL
disables sampling for the thread.
Parameters
callback
address of the callback function or
NULL
custom
opaque data that is passed to the callback function by the Intel® Trace Collector; can be used by the callback function to identify the thread or enabled counters
ncounters
upper limit for the number of counters returned by the callback. It is not a problem to specify a number that is larger than the one that will be actually used, because the extra memory provided to the callback function will be reused efficiently.
Return values
Returns error code

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.