---
name: "MPI_T_pvar_readreset"
section: "3"
platform: "linux"
package: "openmpi"
version: "5.0.11-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/MPI_T_pvar_readreset"
---

# MPI\_T\_pvar\_readreset(3)

*MPI\_T\_pvar\_readreset* — Atomically read and reset the value of a performance variable

## SYNTAX

### C Syntax

```
#include <mpi.h>
int MPI_T_pvar_readreset(MPI_T_pvar_session session, MPI_T_pvar_handle handle, const void *buf)
```

## INPUT PARAMETERS

- •

  **session**: Performance experiment session.

- •

  **handle**: Performance variable handle.

- •

  **buf**: Initial address of storage location for variable value.

## DESCRIPTION

*MPI\_T\_pvar\_readreset* atomically queries and resets the value of a performance variable bound to the handle specified by *handle* in the session specified by *session*. The result is stored in the buffer pointed to by *buf*. This function can only be used with performance variables that are atomic and not readonly. The caller must ensure that the buffer pointed to by *buf* is large enough to hold the entire value of the performance variable.

## ERRORS

*MPI\_T\_pvar\_readreset* will fail if:

- •

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

- •

  **MPI\_T\_ERR\_INVALID\_HANDLE**: The handle is invalid or not associated with the session

- •

  **MPI\_T\_ERR\_INVALID\_SESSION**: Session argument is not a valid session

- •

  **MPI\_T\_ERR\_PVAR\_NO\_ATOMIC**: Variable cannot be read and written atomically

- •

  **MPI\_T\_ERR\_PVAR\_NO\_WRITE**: Variable cannot be reset

**SEE ALSO:**

- •

  *MPI\_T\_pvar\_handle\_alloc*

- •

  *MPI\_T\_pvar\_get\_info*

- •

  *MPI\_T\_pvar\_session\_create*

- •

  *MPI\_T\_pvar\_read*

- •

  *MPI\_T\_pvar\_reset*

## COPYRIGHT

2003-2026, The Open MPI Community