# 17.2.350. MPI_T_category_get_num

MPI_T_category_get_num — Query the number of categories

## 17.2.350.1. SYNTAX

### 17.2.350.1.1. C Syntax

    #include <mpi.h>

    int MPI_T_category_get_num(int *num_cat)

## 17.2.350.2. OUTPUT PARAMETERS

- `num_cat`: Current number of categories

## 17.2.350.3. DESCRIPTION

MPI_T_category_get_num can be used to query the current number of categories.

## 17.2.350.4. ERRORS

MPI_T_category_get_num will fail if:

- `MPI_T_ERR_NOT_INITIALIZED`: The MPI Tools interface not initialized