SHMEM_LONGDOUBLE_IGET(3)

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💅 SHMEM_LONGDOUBLE_IGET(3) — Open MPI edition ✨

okay so first things first, bestie: this page is the group chat for a whole fam of shmem_*_iget calls, and the queen bee in the title is shmem_longdouble_iget. The header says SHMEM_LONGDOUBLE_IGET(3) and the manual is Open MPI — so yes, we're in MPI land, put your lanyard on 🎀

The whole squad showing up on this page:

and what do they all do? Transfers strided data from a specified processing element (PE). that's the whole vibe. strided data, one PE to another, no cap 🌈

🌸 SYNOPSIS 🌸

C or C++:

#include <mpp/shmem.h>

void shmem_iget32(void *target, const void *source,
  ptrdiff_t tst, ptrdiff_t sst, size_t len, int pe)

void shmem_iget64(void *target, const void *source,
  ptrdiff_t tst, ptrdiff_t sst, size_t len, int pe)

void shmem_iget128(void *target, const void *source,
  ptrdiff_t tst, ptrdiff_t sst, size_t len, int pe)

void shmem_int_iget(int *target, const int *source,
  ptrdiff_t tst, ptrdiff_t sst, size_t len, int pe)

void shmem_double_iget(double *target, const double *source,
  ptrdiff_t tst, ptrdiff_t sst, size_t len, int pe)

void shmem_float_iget(float *target, const float *source,
  ptrdiff_t tst, ptrdiff_t sst, size_t len, int pe)

void shmem_long_iget(long *target, const long *source,
  ptrdiff_t tst, ptrdiff_t sst, size_t len, int pe)

void shmem_longdouble_iget(long double *target,
  const long double *source, ptrdiff_t tst, ptrdiff_t sst,size_t len, int pe)

void shmem_longlong_iget(long long *target,
  const long long *source, ptrdiff_t tst, ptrdiff_t sst, size_t len, int pe)

void shmem_short_iget(short *target,
  const short *source, ptrdiff_t tst, ptrdiff_t sst, size_t len, int pe)

(not me pointing out that sst,size_t len with no space in shmem_longdouble_iget — that's literally how it's written, we stan an icon who doesn't fix typos 💀)

Fortran besties, this one's for you:

INCLUDE "mpp/shmem.fh"

INTEGER tst, sst, len, pe

CALL SHMEM_COMPLEX_IGET(target, source, tst, sst, len,
& pe)

CALL SHMEM_DOUBLE_IGET(target, source, tst, sst, len,
& pe)

CALL SHMEM_IGET4(target, source, tst, sst, len, pe)

CALL SHMEM_IGET8(target, source, tst, sst, len, pe)

CALL SHMEM_IGET32(target, source, tst, sst, len, pe)

CALL SHMEM_IGET64(target, source, tst, sst, len, pe)

CALL SHMEM_IGET128(target, source, tst, sst, len, pe)

CALL SHMEM_INTEGER_IGET(target, source, tst, sst, len,
& pe)

CALL SHMEM_LOGICAL_IGET(target, source, tst, sst, len,
& pe)

CALL SHMEM_REAL_IGET(target, source, tst, sst, len, pe)

🦋 DESCRIPTION 🦋

so the strided get routines retrieve array data available at address source on remote PE (pe). the elements of the source array are separated by a stride sst. once the data is received, it gets stored at the local memory address target, separated by stride tst. the routines return when the data has been copied into the local target array. like, actually returned — done, dusted, data delivered 🫶

The arguments are as follows:

  • target — Array to be updated on the local PE. she's the glow-up destination ✨
  • source — Array containing the data to be copied on the remote PE.
  • tst — The stride between consecutive elements of the target array. The stride is scaled by the element size of the target array. A value of 1 indicates contiguous data. tst must be of type integer. If you are calling from Fortran, it must be a default integer value.
  • sst — The stride between consecutive elements of the source array. The stride is scaled by the element size of the source array. A value of 1 indicates contiguous data. sst must be of type integer. If you are calling from Fortran, it must be a default integer value.
  • len — Number of elements in the target and source arrays. len must be of type integer. If you are using Fortran, it must be a constant, variable, or array element of default integer type.
  • pe — PE number of the remote PE. pe must be of type integer. If you are using Fortran, it must be a constant, variable, or array element of default integer type.

The target and source data objects must conform to typing constraints, which are as follows (this is the vibe check, and honestly it's giving strict):

  • shmem_iget32, shmem_iget4 — Any noncharacter type that has a storage size equal to 32 bits.
  • shmem_iget64, shmem_iget8 — Any noncharacter type that has a storage size equal to 64 bits.
  • shmem_iget128 — Any noncharacter type that has a storage size equal to 128 bits.
  • shmem_short_iget — Elements of type short.
  • shmem_int_iget — Elements of type int.
  • shmem_long_iget — Elements of type long.
  • shmem_longlong_iget — Elements of type long long.
  • shmem_float_iget — Elements of type float.
  • shmem_double_iget — Elements of type double.
  • shmem_longdouble_iget — Elements of type long double.
  • SHMEM_COMPLEX_IGET — Elements of type complex of default size.
  • SHMEM_DOUBLE_IGET — (Fortran) Elements of type double precision.
  • SHMEM_INTEGER_IGET — Elements of type integer.
  • SHMEM_LOGICAL_IGET — Elements of type logical.
  • SHMEM_REAL_IGET — Elements of type real.

okay and then the page literally lists these again, so here we go, encore performance 🎤 (yes, fr fr, they're on the original twice — I'm not the one who decided that, I'm just the messenger):

  • shmem_longdouble_iget — Elements of type long double.
  • SHMEM_COMPLEX_IGET — Elements of type complex of default size.
  • SHMEM_DOUBLE_IGET — (Fortran) Elements of type double precision.
  • SHMEM_INTEGER_IGET — Elements of type integer.
  • SHMEM_LOGICAL_IGET — Elements of type logical.
  • SHMEM_REAL_IGET — Elements of type real.

If you are using Fortran, data types must be of default size. For example, a real variable must be declared as REAL, REAL*4, or REAL(KIND=4). no sneaky double-wide shenanigans, bestie 💅

📌 NOTES 📌

See intro_shmem(3) for a definition of the term remotely accessible. (iykyk, but if you don't, go read that one, it's the prequel 🎀)

🍓 EXAMPLES 🍓

The following simple example uses shmem_logical_iget in a Fortran program. Compile this example with the -lsma compiler option.

PROGRAM STRIDELOGICAL
  LOGICAL SOURCE(10), TARGET(5)
  SAVE SOURCE ! SAVE MAKES IT REMOTELY ACCESSIBLE
  DATA SOURCE /.T.,.F.,.T.,.F.,.T.,.F.,.T.,.F.,.T.,.F./
  DATA TARGET / 5*.F. /

  CALL START_PES(2)
  IF (MY_PE() .EQ. 0) THEN
    CALL SHMEM_LOGICAL_IGET(TARGET, SOURCE, 1, 2, 5, 1)
    PRINT*,'TARGET AFTER SHMEM_LOGICAL_IGET:',TARGET
  ENDIF
  CALL SHMEM_BARRIER_ALL
END

look at that SAVE SOURCE comment — SAVE MAKES IT REMOTELY ACCESSIBLE — the manpage is literally yelling it at us in all caps and honestly? deserved 👑

👀 SEE ALSO 👀

2003-2026, The Open MPI Community

and that's the page, bestie 🧚✨ filed under May 14, 2026, brought to you by the Open MPI girlies of SHMEM_LONGDOUBLE_IGET(3) — go forth and stride, and remember: 1 means contiguous, so keep it tight 🎀💖

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