MPI\_T\_CATEGORY\_CHANGED(3) Open MPI MPI\_T\_CATEGORY\_CHANGED(3)

MPI\_T\_category\_changed — Get a timestamp for the categories

# [SYNTAX](#SYNTAX)

## [C Syntax](#C_Syntax)

```
#include <mpi.h>
int MPI_T_category_changed(int *stamp)
```

# [INPUT PARAMETERS](#INPUT_PARAMETERS)

•

**stamp**: A virtual time stamp to indicate the last change to the categories.

# [DESCRIPTION](#DESCRIPTION)

If two subsequent calls to this routine return the same timestamp, it is guaranteed that no categories have been changed or added. If the timestamp from the second call is higher than some categories have been added or changed.

# [ERRORS](#ERRORS)

MPI\_T\_category\_changed will fail if:

•

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

# [Copyright](#Copyright)

2003-2026, The Open MPI Community

September 23, 2026

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Document: MPI_T_category_changed(3) from openmpi-cuda-13.0 5.0.11-r0 (Chainguard OS)
Source: https://github.com/open-mpi/ompi