Frees a communication request object


#include "mpi.h"
int MPI_Request_free( request )
MPI_Request *request;

Input Parameter

communication request (handle)


This routine is normally used to free persistent requests created witheither MPI_Recv_init or MPI_Send_init and friends. However, it can beused to free a request created with MPI_Irecv or MPI_Isend and friends; in that case the use can not use the test/wait routines on the request.

It is permitted to free an active request. However, once freed, you can notuse the request in a wait or test routine (e.g., MPI_Wait).

Notes for Fortran

All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK) havean additional argument ierr at the end of the argument list. ierris an integer and has the same meaning as the return value of the routinein C. In Fortran, MPI routines are subroutines, and are invoked with thecall statement.

All MPI objects (e.g., MPI_Datatype, MPI_Comm) are of type INTEGERin Fortran.


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 lastargument. Before the value is returned, the current MPI error handler iscalled. By default, this error handler aborts the MPI job. The error handlermay be changed with MPI_Errhandler_set; the predefined error handlerMPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue pastan error.

No error; MPI routine completed successfully.
Invalid MPI_Request. Either null or, in the case of a MPI_Start or MPI_Startall, not a persistent request.
Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., MPI_ERR_RANK).

See Also

also: MPI_Isend, MPI_Irecv, MPI_Issend, MPI_Ibsend, MPI_Irsend,
MPI_Recv_init, MPI_Send_init, MPI_Ssend_init, MPI_Rsend_init, MPI_Wait, MPI_Test, MPI_Waitall, MPI_Waitany, MPI_Waitsome, MPI_Testall, MPI_Testany, MPI_Testsome