---
name: "MPI_Grequest_complete.openmpi"
section: "3"
platform: "linux"
package: "openmpi-doc"
version: "5.0.7-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/MPI_Grequest_complete.openmpi"
---

# MPI\_Grequest\_complete.openmpi(3)

*MPI\_Grequest\_complete* — Reports that a generalized request is complete.

## SYNTAX

### C Syntax

```
#include <mpi.h>
int MPI_Grequest_complete(MPI_Request request)
```

### Fortran Syntax

```
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_GREQUEST_COMPLETE(REQUEST, IERROR)
    INTEGER REQUEST, IERROR
```

### Fortran 2008 Syntax

```
USE mpi_f08
MPI_Grequest_complete(request, ierror)
    TYPE(MPI_Request), INTENT(IN) :: request
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror
```

## INPUT/OUTPUT PARAMETER

- •

  **request** : Generalized request (handle).

## OUTPUT PARAMETER

- •

  **ierror** : Fortran only: Error status (integer).

## DESCRIPTION

*MPI\_Grequest\_complete* informs MPI that the operations represented by the generalized request **request** are complete. A call to MPI\_Wait(request, status)\`\` will return, and a call to MPI\_Test(request, flag, status)\`\` will return flag=true only after a call to *MPI\_Grequest\_complete* has declared that these operations are complete.

MPI imposes no restrictions on the code executed by the callback functions. However, new nonblocking operations should be defined so that the general semantic rules about MPI calls such as *MPI\_Test*, *MPI\_Request\_free*, or *MPI\_Cancel* still hold. For example, all these calls are supposed to be local and nonblocking. Therefore, the callback functions **query\_fn**, **free\_fn**, or **cancel\_fn** should invoke blocking MPI communication calls only if the context is such that these calls are guaranteed to return in finite time. Once *MPI\_Cancel* has been invoked, the canceled operation should complete in finite time, regardless of the state of other processes (the operation has acquired “local” semantics). It should either succeed or fail without side-effects. The user should guarantee these same properties for newly defined operations.

## ERRORS

Almost all MPI routines return an error value; C routines as the return result of the function and Fortran routines in the last argument.

Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI\_COMM\_SELF and will call the associated MPI error handler. When MPI\_COMM\_SELF is not initialized (i.e., before *MPI\_Init*/*MPI\_Init\_thread*, after *MPI\_Finalize*, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling *MPI\_Comm\_set\_errhandler* on MPI\_COMM\_SELF when using the World model, or the mpi\_initial\_errhandler CLI argument to mpiexec or info key to *MPI\_Comm\_spawn*/*MPI\_Comm\_spawn\_multiple*. If no other appropriate error handler has been set, then the MPI\_ERRORS\_RETURN error handler is called for MPI I/O functions and the MPI\_ERRORS\_ABORT error handler is called for all other MPI functions.

Open MPI includes three predefined error handlers that can be used:

- •

  **MPI\_ERRORS\_ARE\_FATAL** Causes the program to abort all connected MPI processes.

- •

  **MPI\_ERRORS\_ABORT** An error handler that can be invoked on a communicator, window, file, or session. When called on a communicator, it acts as if *MPI\_Abort* was called on that communicator. If called on a window or file, acts as if *MPI\_Abort* was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, aborts only the local process.

- •

  **MPI\_ERRORS\_RETURN** Returns an error code to the application.

MPI applications can also implement their own error handlers by calling:

- •

  *MPI\_Comm\_create\_errhandler* then *MPI\_Comm\_set\_errhandler*

- •

  *MPI\_File\_create\_errhandler* then *MPI\_File\_set\_errhandler*

- •

  *MPI\_Session\_create\_errhandler* then *MPI\_Session\_set\_errhandler* or at *MPI\_Session\_init*

- •

  *MPI\_Win\_create\_errhandler* then *MPI\_Win\_set\_errhandler*

Note that MPI does not guarantee that an MPI program can continue past an error.

See the *MPI man page* for a full list of *MPI error codes*.

See the Error Handling section of the MPI-3.1 standard for more information.

## COPYRIGHT

2003-2025, The Open MPI Community