MPI\_T\_PVAR\_SESSION\_CREATE(3) Open MPI MPI\_T\_PVAR\_SESSION\_CREATE(3)

MPI\_T\_pvar\_session\_create, MPI\_T\_pvar\_session\_free <#mpi-t-pvar-session-free> - Create/free performance variable session

# [SYNTAX](#SYNTAX)

## [C Syntax](#C_Syntax)

```
#include <mpi.h>
int MPI_T_pvar_session_create(MPI_T_pvar_session *session)
int MPI_T_pvar_session_free(MPI_T_pvar_session *session)
```

# [DESCRIPTION](#DESCRIPTION)

MPI\_T\_pvar\_session\_create creates a session for accessing performance variables. The new session is returned in the *session* parameter.

MPI\_T\_pvar\_session\_free &lt;#mpi-t-pvar-session-free&gt; releases a session allocated by MPI\_T\_pvar\_session\_create and sets the *session* parameter to MPI\_T\_PVAR\_SESSION\_NULL.

# [ERRORS](#ERRORS)

MPI\_T\_pvar\_session\_create will fail if:

- **MPI\_T\_ERR\_NOT\_INITIALIZED**: The MPI Tools interface not initialized
- **MPI\_T\_ERR\_MEMORY**: Out of memory
- **MPI\_T\_ERR\_OUT\_OF\_SESSIONS**: No more sessions available

MPI\_T\_pvar\_session\_free &lt;#mpi-t-pvar-session-free&gt; will fail if:

- **MPI\_T\_ERR\_NOT\_INITIALIZED**: The MPI Tools interface not initialized
- **MPI\_T\_ERR\_INVALID\_SESSION**: The session parameter is not a valid session

# [Copyright](#Copyright)

2003-2026, The Open MPI Community

November 1, 2026

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