MPI\_T\_CATEGORY\_GET\_NUM(3) Open MPI MPI\_T\_CATEGORY\_GET\_NUM(3)

MPI\_T\_category\_get\_num — Query the number of categories

# [SYNTAX](#SYNTAX)

## [C Syntax](#C_Syntax)

```
#include <mpi.h>
int MPI_T_category_get_num(int *num_cat)
```

# [OUTPUT PARAMETERS](#OUTPUT_PARAMETERS)

•

**num\_cat**: Current number of categories

# [DESCRIPTION](#DESCRIPTION)

MPI\_T\_category\_get\_num can be used to query the current number of categories.

# [ERRORS](#ERRORS)

MPI\_T\_category\_get\_num will fail if:

•

**MPI\_T\_ERR\_NOT\_INITIALIZED**: The MPI Tools interface not initialized

# [Copyright](#Copyright)

2003-2026, The Open MPI Community

November 1, 2026

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Document: MPI_T_category_get_num(3) from openmpi-cuda-12.9 5.0.11-r1 (Chainguard OS)
Source: https://github.com/open-mpi/ompi