SHMEM_INT_FADD(3)

🌸 SHMEM_INT_FADD(3) — the Open MPI fadd page 🌸

okay so bestie, welcome to the Open MPI manual page for the shmem_*_fadd girlies. they do one little thing and they do it atomically, which is honestly main character energy. 💅

💖 NAME 💖

shmem_int4_fadd(3), shmem_int8_fadd(3), shmem_int_fadd(3), shmem_long_fadd(3), shmem_longlong_fadd(3) — performs an atomic fetch-and-add operation on a remote data object.

✨ SYNOPSIS ✨

C or C++:

          #include <mpp/shmem.h>

          int shmem_int_fadd(int *target, int value, int pe)

          long shmem_long_fadd(long *target, long value, int pe)

          long long shmem_longlong_fadd(long long *target, longlong value,
            int pe)

Fortran:

          INCLUDE "mpp/shmem.fh"

          INTEGER pe

          INTEGER(KIND=4) SHMEM_INT4_FADD, ires, target, value
          ires = SHMEM_INT4_FADD(target, value, pe)

          INTEGER(KIND=8) SHMEM_INT8_FADD, ires, target, value
          ires = SHMEM_INT8_FADD(target, value, pe)

🦋 DESCRIPTION 🦋

so the shmem_fadd functions do an atomic fetch-and-add operation. an atomic fetch-and-add operation fetches the old target and adds value to target without the possibility of another process updating target between the time of the fetch and the update. like, no sneaky little interruption, no cap. these routines add value to target on Processing Element (PE) pe and return the previous contents of target as an atomic operation. periodt. 💫

the arguments are giving:

• target — the remotely accessible integer data object to be updated on the remote PE. the type of target should match that implied in the SYNOPSIS section.
• value — the value to be atomically added to target. the type of value should match that implied in the SYNOPSIS section.
• pe — an integer that indicates the PE number on which target is to be updated. if you’re using Fortran, it must be a default integer value.

🌈 NOTES 🌈

quick vocab check, bestie: the term remotely accessible is defined in intro_shmem(3). iykyk. 🫶

🎀 RETURN VALUES 🎀

the contents that had been at the target address on the remote PE prior to the atomic addition operation. that’s the little gift it hands back. 🍓

⭐ SEE ALSO ⭐

• intro_shmem(3)

👑 COPYRIGHT 👑

2003-2026, The Open MPI Community

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mwah 💋 — this was SHMEM_INT_FADD(3) from Open MPI, dated May 14, 2026, and that’s the footer folded into a little bow for you. 🎀✨