---
name: "MPI_T_category_get_cvars.openmpi"
section: "3"
platform: "linux"
package: "openmpi-doc"
version: "5.0.7-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/MPI_T_category_get_cvars.openmpi"
---

# MPI\_T\_category\_get\_cvars.openmpi(3)

*MPI\_T\_category\_get\_cvars* — Query which control variables are in a category

## SYNTAX

### C Syntax

```
#include <mpi.h>
int MPI_T_category_get_cvars(int cat_index, int len, int indices[])
```

## INPUT PARAMETERS

- •

  **cat\_index**: Index of the category to be queried.

- •

  **len**: The length of the indices array.

## OUTPUT PARAMETERS

- •

  **indices**: An integer array of size len, indicating control variable indices.

## DESCRIPTION

*MPI\_T\_category\_get\_cvars* can be used to query which control variables are contained in a particular category.

## ERRORS

*MPI\_T\_category\_get\_cvars* will fail if:

- •

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

- •

  **MPI\_T\_ERR\_INVALID\_INDEX**: The category index is invalid

## COPYRIGHT

2003-2025, The Open MPI Community