# 17.2.362. MPI_T_pvar_get_num

MPI_T_pvar_get_num — Query the number of performance variables

## 17.2.362.1. SYNTAX

### 17.2.362.1.1. C Syntax

    #include <mpi.h>

    int MPI_T_pvar_get_num(int *num_pvar)

## 17.2.362.2. OUTPUT PARAMETERS

- `num_pvar`: Current number of performance variables.

## 17.2.362.3. DESCRIPTION

MPI_T_pvar_get_num can be used to query the current number of performance variables. The number of performance variables may increase throughout the execution of the process but will never decrease.

## 17.2.362.4. ERRORS

MPI_T_pvar_get_num will fail if:

- `MPI_T_ERR_NOT_INITIALIZED`: The MPI Tools interface not initialized