NAME¶
shmem_double_swap(3), shmem_float_swap(3),
shmem_int_swap(3), shmem_long_swap(3), shmem_swap(3),
shmem_int4_swap(3), shmem_int8_swap(3),
shmem_real4_swap(3), shmem_real8_swap(3),
shmem_longlong_swap(3) - Performs an atomic swap to a remote data
object
SYNOPSIS¶
C or C++:
#include <mpp/shmem.h>
double shmem_double_swap(double *target, double value,
int pe);
float shmem_float_swap(float *target, float value, int pe);
int shmem_int_swap(int *target, int value, int pe);
long shmem_long_swap(long *target, long value, int pe);
long long shmem_longlong_swap(long long *target,
long long value, int pe);
long shmem_swap(long *target, long value, int pe);
Fortran:
INCLUDE "mpp/shmem.fh"
INTEGER pe
INTEGER SHMEM_SWAP
ires = SHMEM_SWAP(target, value, pe)
INTEGER(KIND=4) SHMEM_INT4_SWAP
ires = SHMEM_INT4_SWAP(target, value, pe)
INTEGER(KIND=8) SHMEM_INT8_SWAP
ires = SHMEM_INT8_SWAP(target, value, pe)
REAL(KIND=4) SHMEM_REAL4_SWAP
res = SHMEM_REAL4_SWAP(target, value, pe)
REAL(KIND=8) SHMEM_REAL8_SWAP
res = SHMEM_REAL8_SWAP(target, value, pe)
DESCRIPTION¶
The atomic swap routines write value to address target on PE pe,
and return the previous contents of target in one atomic operation.
The arguments are as follows:
- target
- The remotely accessible integer data object to be updated on the remote
PE. If you are using C/C++, the type of target should match that implied
in the SYNOPSIS section. If you are using Fortran, it must be of the
following type:
- SHMEM_SWAP: Integer of default kind
- SHMEM_INT4_SWAP: 4-byte integer
- SHMEM_INT8_SWAP: 8-byte integer
- SHMEM_REAL4_SWAP: 4-byte real
- SHMEM_REAL8_SWAP: 8-byte real
- value
- Value to be atomically written to the remote PE. value is the same type as
target.
- 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.
NOTES¶
The term remotely accessible is defined in intro_shmem(3).
RETURN VALUES¶
The contents that had been at the target address on the remote PE prior to the
swap is returned.