MPI_TESTALL(3)					     Open MPI					    MPI_TESTALL(3)

MPI_Testall — Tests for the completion of all previously initiated communications in a list.

SYNTAX
   C Syntax
	  #include <mpi.h>

	  int MPI_Testall(int count, MPI_Request array_of_requests[],
	       int *flag, MPI_Status array_of_statuses[])

   Fortran Syntax
	  USE MPI
	  ! or the older form: INCLUDE 'mpif.h'
	  MPI_TESTALL(COUNT, ARRAY_OF_REQUESTS, FLAG, ARRAY_OF_STATUSES,
		       IERROR)
	       LOGICAL FLAG
	       INTEGER COUNT, ARRAY_OF_REQUESTS(*)
	       INTEGER ARRAY_OF_STATUSES(MPI_STATUS_SIZE,*), IERROR

   Fortran 2008 Syntax
	  USE mpi_f08
	  MPI_Testall(count, array_of_requests, flag, array_of_statuses, ierror)
	       INTEGER, INTENT(IN) :: count
	       TYPE(MPI_Request), INTENT(INOUT) :: array_of_requests(count)
	       LOGICAL, INTENT(OUT) :: flag
	       TYPE(MPI_Status) :: array_of_statuses(*)
	       INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS
       • count: Lists length (integer).

       • array_of_requests: Array of requests (array of handles).

OUTPUT PARAMETERS
       • flag: True if previously initiated communications are complete (logical.)

       • array_of_statuses: Array of status objects (array of status).

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

DESCRIPTION
       Returns	flag = true if all communications associated with active handles in the array have completed (this
       includes the case where no handle in the list is active). In this case, each status entry that  corresponds
       to  an  active  handle  request is set to the status of the corresponding communication; if the request was
       allocated by a  nonblocking  communication  call	 then  it  is  deallocated,  and  the  handle  is  set	to
       MPI_REQUEST_NULL. Each status entry that corresponds to a null or inactive handle is set to empty.

       Otherwise,  flag	 =  false  is  returned,  no  request is modified and the values of the status entries are
       undefined. This is a local operation.

       If your application does not need to examine the array_of_statuses field, you can save resources	 by  using
       the  predefined	constant  MPI_STATUSES_IGNORE  can  be	used  as a special value for the array_of_statuses
       argument.

       Errors that occurred during the execution of MPI_Testall are handled  in	 the  same  manner  as	errors	in
       MPI_Waitall <#mpi-waitall>.

NOTE
       flag  is	 true only if all requests have completed. Otherwise, flag is false, and neither array_of_requests
       nor array_of_statuses is modified.

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>/MPI_Init_thread  <#mpi-init-thread>,
       after  MPI_Finalize  <#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	<#
       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>/MPI_Comm_spawn_multiple	<#
       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 <#mpi-abort> was called on that communicator. If called
	 on a window or file, acts as if MPI_Abort <#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	 <#mpi-comm-create-errhandler>	   then	    MPI_Comm_set_errhandler	<#
	 mpi-comm-set-errhandler>

       • MPI_File_create_errhandler	<#mpi-file-create-errhandler>	  then	   MPI_File_set_errhandler	<#
	 mpi-file-set-errhandler>

       • MPI_Session_create_errhandler	 <#mpi-session-create-errhandler>   then   MPI_Session_set_errhandler	<#
	 mpi-session-set-errhandler> or at MPI_Session_init <#mpi-session-init>

       • MPI_Win_create_errhandler	<#mpi-win-create-errhandler>	  then	    MPI_Win_set_errhandler	<#
	 mpi-win-set-errhandler>

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

       See the MPI man page <#open-mpi> for a full list of MPI error codes <#open-mpi-errors>.

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

       For  each  invocation  of  MPI_Testall,	if  one or more requests generate an MPI error, only the first MPI
       request that caused an error will be passed to its corresponding error handler.	No  other  error  handlers
       will  be invoked (even if multiple requests generated errors). However, all requests that generate an error
       will have a relevant error code set in the corresponding status.MPI_ERROR field (unless MPI_STATUSES_IGNORE
       was used).

       If the invoked error handler allows MPI_Testall to return to the caller, the value  MPI_ERR_IN_STATUS  will
       be returned in the C and Fortran bindings.

       See also:

	  • MPI_Comm_set_errhandler <#mpi-comm-set-errhandler>

	  • MPI_File_set_errhandler <#mpi-file-set-errhandler>

	  • MPI_Test <#mpi-test>

	  • MPI_Testany <#mpi-testany>

	  • MPI_Testsome <#mpi-testsome>

	  • MPI_Wait <#mpi-wait>

	  • MPI_Waitall <#mpi-waitall>

	  • MPI_Waitany <#mpi-waitany>

	  • MPI_Waitsome <#mpi-waitsome>

	  • MPI_Win_set_errhandler <#mpi-win-set-errhandler>

Copyright
       2003-2026, The Open MPI Community

						   Mar 05, 2026					    MPI_TESTALL(3)
