NAME¶

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

SYNOPSIS¶

C Interface

#include <papi.h>
int PAPI_num_counters(void);

Fortran Interface

#include fpapi.h
PAPIF_num_counters(C_INT number)

DESCRIPTION¶

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() initializes the library to PAPI_HIGH_LEVEL_INITED if necessary.

RETURN VALUES¶

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

ERRORS¶

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.

EXAMPLES¶

  int num_hwcntrs;


  /*  The installation does not support PAPI */


  if ((num_hwcntrs = PAPI_num_counters()) < 0 )


    handle_error(1);


  /*  The installation supports PAPI, but has no counters */


  if ((num_hwcntrs = PAPI_num_counters()) == 0 )


    fprintf(stderr,"Info:: This machine does not provide hardware counters.0);

BUGS¶

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

SEE ALSO¶

PAPI(3),PAPIF(3)