# 17.2.356. MPI_T_cvar_write

MPI_T_cvar_write — Write the value of a bound control variable

## 17.2.356.1. SYNTAX

### 17.2.356.1.1. C Syntax

    #include <mpi.h>

    int MPI_T_cvar_write(MPI_T_cvar_handle handle, const void *buf)

## 17.2.356.2. INPUT PARAMETERS

- `handle`: Handle of the control variable to be written.

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

## 17.2.356.3. DESCRIPTION

MPI_T_cvar_write sets the value the control variable identified by the handle specified in handle from the buffer provided in buf. The caller must ensure that the buffer specified in buf is large enough to hold the entire value of the control variable. If the variable has global scope, any write call must be issued on all connected MPI processes. For more information see MPI-3 section 14.3.6.

## 17.2.356.4. ERRORS

MPI_T_cvar_write will fail if:

- `MPI_T_ERR_NOT_INITIALIZED`: The MPI Tools interface not initialized

- `MPI_T_ERR_INVALID_HANDLE`: The handle is invalid

- `MPI_T_ERR_CVAR_SET_NOT_NOW`: Variable cannot be set at this moment

- `MPI_T_ERR_CVAR_SET_NEVER`: Variable cannot be set until end of execution

See also

- MPI_T_cvar_handle_alloc

- MPI_T_cvar_get_info