# 18.2.372. MPI_T_pvar_write

MPI_T_pvar_write — Write the value of a control variable

## 18.2.372.1. SYNTAX

### 18.2.372.1.1. C Syntax

    #include <mpi.h>

    int MPI_T_pvar_write(MPI_T_pvar_session session, MPI_T_pvar_handle handle, const void *buf)

## 18.2.372.2. INPUT PARAMETERS

- `session`: Performance experiment session.

- `handle`: Performance variable handle.

- `buf`: Initial address of storage location for variable value.

## 18.2.372.3. DESCRIPTION

MPI_T_pvar_write attempts to set the value of the performance variable identified by the handle specified in handle in the session specified in session. The value to be written is specified in buf. The caller must ensure that the buffer specified in buf is large enough to hold the entire value of the performance variable.

## 18.2.372.4. ERRORS

MPI_T_pvar_write 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_WRITE`: Variable cannot be written

See also

- MPI_T_pvar_handle_alloc

- MPI_T_pvar_get_info

- MPI_T_pvar_session_create