# 18.2.87. shmem_int_fadd

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

## 18.2.87.1. 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)

## 18.2.87.2. DESCRIPTION

shmem_fadd functions perform 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. These routines add value to target on Processing Element (PE) pe and return the previous contents of target as an atomic operation.

The arguments are as follows:

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 are using Fortran, it must be a default integer value.

## 18.2.87.3. NOTES

The term remotely accessible is defined in intro_shmem(3).

## 18.2.87.4. RETURN VALUES

The contents that had been at the target address on the remote PE prior to the atomic addition operation.

See also

intro_shmem(3)