MPI_OP_F2C(3)

🌈 MPI_OP_F2C(3) — Open MPI, but make it a vibe 🌈

Okay bestie, welcome to the glow-up zone. This is the Open MPI manual page for all the handle translation functions, and honestly? It's giving iconic. 💅

✨ NAME ✨

Bestie, this page covers the whole squad of C-to-Fortran and Fortran-to-C handle translators: MPI_Comm_f2c, MPI_Comm_c2f, MPI_File_f2c, MPI_File_c2f, MPI_Info_f2c, MPI_Info_c2f, MPI_Message_f2c, MPI_Message_c2f, MPI_Op_f2c, MPI_Op_c2f, MPI_Request_f2c, MPI_Request_c2f, MPI_Type_f2c, MPI_Type_c2f, MPI_Win_f2c, MPI_Win_c2f — and they translate a C handle into a Fortran handle, or vice versa. Iykyk. ✨

💻 SYNTAX 💻

C Syntax

Okay so here's the exact C syntax, no cap. Copy-paste responsibly:

          #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 🫶

Okay so, bestie, here's the tea ☕. 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. Periodt. 💅

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. Slay. ✨

For example:

• If comm is a valid Fortran handle to a communicator, then MPI_Comm_f2c returns a valid C handle to that same communicator.
• If comm = MPI_COMM_NULL (Fortran value), then MPI_Comm_f2c returns a null C handle.
• If comm is an invalid Fortran handle, then MPI_Comm_f2c returns an invalid C handle.

It's giving very straightforward, ngl. 🦋

⚠️ NOTE ⚠️

💀 This function does not return an error value. Consequently, the result of calling it before MPI_Init or after MPI_Finalize is undefined. So like, don't do that, bestie. Undefined behavior is not the vibe. 🚫

🎀 COPYRIGHT 🎀

This page is brought to you by the 2003-2026, The Open MPI Community. The man page itself is dated Sep 11, 2026. Stay slaying, and remember: handles are just integers with main character energy. 💖✨