---
name: "MPI_T_event_handle_alloc"
section: "3"
platform: "linux"
package: "mpich-doc"
version: "4.0.2-3"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/MPI_T_event_handle_alloc"
---

# MPI\_T\_event\_handle\_alloc(3)

Creates a registration handle for the event type identified by event\_index

## NAME

MPI\_T\_event\_handle\_alloc -  Creates a registration handle for the event type identified by event\_index

## SYNOPSIS

```
int MPI_T_event_handle_alloc(int event_index, void *obj_handle, MPI_Info info,
MPI_T_event_registration *event_registration)
```

## INPUT PARAMETERS

- **event\_index**

  \- index of event type for which the registration handle is to be allocated (integer)

- **obj\_handle**

  \- reference to a handle of the mpi object to which this event is supposed to be bound (pointer)

- **info**

  \- info object (handle)

## OUTPUT PARAMETERS

- **event\_registration**

  \- event registration (handle)

## THREAD AND INTERRUPT SAFETY

This routine is thread-safe.  This means that this routine may be safely used by multiple threads without the need for any user-provided thread locks.  However, the routine is not interrupt safe.  Typically, this is due to the use of memory allocation routines such as  *malloc* or other non-MPICH runtime routines that are themselves not interrupt-safe.

## ERRORS

All MPI routines (except  *MPI\_Wtime* and  *MPI\_Wtick* ) return an error value; C routines as the value of the function and Fortran routines in the last argument.  Before the value is returned, the current MPI error handler is called.  By default, this error handler aborts the MPI job.  The error handler may be changed with  *MPI\_Comm\_set\_errhandler* (for communicators), *MPI\_File\_set\_errhandler* (for files), and  *MPI\_Win\_set\_errhandler* (for RMA windows).  The MPI-1 routine  *MPI\_Errhandler\_set* may be used but its use is deprecated.  The predefined error handler *MPI\_ERRORS\_RETURN* may be used to cause error values to be returned. Note that MPI does  **not** guarantee that an MPI program can continue past an error; however, MPI implementations will attempt to continue whenever possible.

- **MPI\_SUCCESS**

  \- No error; MPI routine completed successfully.

- **MPI\_ERR\_INFO**

  \- Invalid Info

- **MPI\_T\_ERR\_INVALID**

  \- Invalid use of the interface or bad parameter values(s).

- **MPI\_T\_ERR\_INVALID\_INDEX**

  \- Index is invalid or has been deleted.

- **MPI\_T\_ERR\_NOT\_INITIALIZED**

  \- The MPI tool information interface is not initialized.

- **MPI\_ERR\_OTHER**

  \- Other error; use  *MPI\_Error\_string* to get more information about this error code.