MPI_REQUEST_C2F(3)				     Open MPI					MPI_REQUEST_C2F(3)

       MPI_Comm_f2c  <#mpi-comm-f2c>,  MPI_Comm_c2f <#mpi-comm-c2f>, MPI_File_f2c <#mpi-file-f2c>, MPI_File_c2f <#
       mpi-file-c2f>,	MPI_Info_f2c   <#mpi-info-f2c>,	  MPI_Info_c2f	 <#mpi-info-c2f>,    MPI_Message_f2c	<#
       mpi-message-f2c>,  MPI_Message_c2f  <#mpi-message-c2f>, MPI_Op_f2c <#mpi-op-f2c>, MPI_Op_c2f <#mpi-op-c2f>,
       MPI_Request_f2c	<#mpi-request-f2c>,  MPI_Request_c2f,  MPI_Type_f2c   <#mpi-type-f2c>,	 MPI_Type_c2f	<#
       mpi-type-c2f>,  MPI_Win_f2c  <#mpi-win-f2c>,  MPI_Win_c2f  <#mpi-win-c2f>  -  Translates	 a C handle into a
       Fortran handle, or vice versa.

SYNTAX
   C Syntax
	  #include <mpi.h>

	  MPI_Comm MPI_Comm_f2c(MPI_Fint comm)
	  MPI_Fint MPI_Comm_c2f(MPI_Comm comm)

	  MPI_File MPI_File_f2c(MPI_Fint file)
	  MPI_Fint MPI_File_c2f(MPI_File file)

	  MPI_Group MPI_Group_f2c(MPI Fint group)
	  MPI_Fint MPI_Group_c2f(MPI Group group)

	  MPI_Info MPI_Info_f2c(MPI_Fint info)
	  MPI_Fint MPI_Info_c2f(MPI_Info info)

	  MPI_Message MPI_Message_f2c(MPI_Fint message)
	  MPI_Fint MPI_Message_c2f(MPI_Message message)

	  MPI_Op MPI_Op_f2c(MPI_Fint op)
	  MPI_Fint MPI_Op_c2f(MPI_Op op)

	  MPI_Request MPI_Request_f2c(MPI_Fint request)
	  MPI_Fint MPI_Request_c2f(MPI_Request request)

	  MPI_Datatype MPI_Type_f2c(MPI_Fint datatype)
	  MPI_Fint MPI_Type_c2f(MPI_Datatype datatype)

	  MPI_Win MPI_Win_f2c(MPI_Fint win)
	  MPI_Fint MPI_Win_c2f(MPI_Win win)

DESCRIPTION
       Handles are passed between Fortran and C by using an explicit C wrapper to convert  Fortran  handles  to	 C
       handles.	 There	is no direct access to C handles in Fortran. The type definition MPI_Fint is provided in C
       for an integer of the size that matches a Fortran INTEGER; usually, MPI_Fint will be equivalent to int. The
       handle translation functions are provided in C to convert from a Fortran handle (which is an integer) to	 a
       C handle, and vice versa.

       For example, if comm is a valid Fortran handle to a communicator, then MPI_Comm_f2c <#mpi-comm-f2c> returns
       a  valid	 C handle to that same communicator; if comm = MPI_COMM_NULL (Fortran value), then MPI_Comm_f2c <#
       mpi-comm-f2c> returns a null C handle;  if  comm	 is  an	 invalid  Fortran  handle,  then  MPI_Comm_f2c	<#
       mpi-comm-f2c> returns an invalid C handle.

NOTE
       This  function  does  not  return an error value. Consequently, the result of calling it before MPI_Init <#
       mpi-init> or after MPI_Finalize <#mpi-finalize> is undefined.

Copyright
       2003-2026, The Open MPI Community

						   Mar 05, 2026					MPI_REQUEST_C2F(3)
