NAME

PAPI_num_counters - PAPI High Level: get the number of hardware counters available on the system

CONTENTS

Synopsis
Description
Return Values
Errors
Examples
Author
Bugs
See Also

C Interface

#include <papi.h> 

int PAPI_num_counters(void); 

Fortran Interface

#include fpapi.h 

PAPIF_num_counters(C_INT number) 

PAPI_num_counters() returns the optimal length of the values array for the high level functions. This value corresponds to the number of hardware counters supported by the current substrate. PAPI_num_counters() initialises the library using PAPI_library_init if necessary.

On success, this function returns the number of hardware counters available.
On error, a negative error code is returned.

PAPI_EINVAL
	papi.h is different from the version used to compile the PAPI library.
PAPI_ENOMEM
	Insufficient memory to complete the operation.
PAPI_ESYS
	A system or C library call failed inside PAPI, see the errno variable.

  int Events[2] = { PAPI_TOT_CYC, PAPI_TOT_INS };
  int num_hwcntrs = 0;
        
  if ((num_hwcntrs = PAPI_num_counters()) != PAPI_OK)
    handle_error(1);

  if (num_hwcntrs > 2)
    num_hwcntrs = 2;

  /* Start counting events */

  if (PAPI_start_counters(Events, num_hwcntrs) != PAPI_OK)
    handle_error(1);

Philip J. Mucci <mucci@cs.utk.edu>

If you don’t call this function, your application could core dump.

PAPI_start_counters (3), PAPI_read_counters (3), PAPI_stop_counters (3),
The PAPI Web Site: http://icl.cs.utk.edu/projects/papi