# 18.2.349. MPI_T_category_get_num

MPI_T_category_get_num — Query the number of categories

## 18.2.349.1. SYNTAX

### 18.2.349.1.1. C Syntax

    #include <mpi.h>

    int MPI_T_category_get_num(int *num_cat)

## 18.2.349.2. OUTPUT PARAMETERS

- `num_cat`: Current number of categories

## 18.2.349.3. DESCRIPTION

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

## 18.2.349.4. ERRORS

MPI_T_category_get_num will fail if:

- `MPI_T_ERR_NOT_INITIALIZED`: The MPI Tools interface not initialized