qnx_trace_trigger()

cause a proxy to be triggered when a trace buffer reaches a given level

Synopsis:

#include <sys/trace.h>
int qnx_trace_trigger( pid_t proc_pid, 
                       long hi_water,
                       pid_t proxy );

The qnx_trace_trigger() function causes the specified proxy to be triggered when the amount of data in the trace buffer reaches the hi_water mark. To have a proxy triggered, qnx_trace_open() must have been previously called.

If hi_water is -1, the trigger level isn't changed, otherwise it is set.

If proxy is -1, it isn't changed. If it's zero, triggering is disabled, otherwise it's set to the specified proxy.

The proc_pid argument is the process ID of the process manager, Proc. If proc_pid is zero or PROC_PID, the Proc on the current node is used, and the trace buffer on the current node is accessed.

Returns:

0: Success
-1: An error occurred. errno is set to indicate the error.

Errors:

EINVAL: The qnx_trace_open() function hasn't been called.
ENOSYS: The process manager doesn't support trace calls.
ESRCH: The proc_pid is invalid.

Examples:

/*
 * Change the high water level
 */
#include <stdio.h>
#include <sys/trace.h>

void main( int argc, char *argv[] )
  {

    if( argc > 1 ) {
      printf( "Changing high water to %ld, ",
          atol( argv[1] ) );
      if( qnx_trace_trigger( 0, atol( argv[1] ), -1 )
          == -1 ) {
          printf( "Failed\n" );
      } else {
          printf( "Successful\n" );
      }
    }
  }

Classification:

QNX

Safety:
Interrupt handler	No
Signal handler	Yes, but modifies errno
Thread	Yes