SHMEM_LONGLONG_GET(3)

📦
version 5.0.10 · 4 versions
, in ubuntu stonking

💖 NAME 💖

okay so this page is filed under SHMEM_LONGLONG_GET(3), and it's from the Open MPI manual, section 3 (the library-calls section, iykyk ✨). but bestie, it's not just one function — it's a whole girlband touring together, and every single member gets a shoutout here:

and the plot of the whole album? they transfer data from a specified processing element (PE). that's it, that's the serve. 🫶

🌈 SYNOPSIS 🌈

so for the C / C++ girlies you include <mpp/shmem.h> and then pick your fighter:

#include <mpp/shmem.h>

void shmem_get32(void *target, const void *source,
  size_t len, int pe)

void shmem_get64(void *target, const void *source,
  size_t len, int pe)

void shmem_get128(void *target, const void *source,
  size_t len, int pe)

void shmem_getmem(void *target, const void *source,
  size_t len, int pe)

void shmem_int_get(int *target, const int *source,
  size_t len, int pe)

void shmem_double_get(double *target, const double *source,
  size_t len, int pe)

void shmem_float_get(float *target, const float *source,
  size_t len, int pe)

void shmem_long_get(long *target, const long *source,
  size_t len, int pe)

void shmem_longdouble_get(long double *target,
  const long double *source, size_t len, int pe)

void shmem_longlong_get(long long *target,
  const long long *source, size_t len, int pe)

void shmem_short_get(short *target,
  const short *source, size_t len, int pe)

and for the Fortran besties 🎀 — different include, same energy:

INCLUDE "mpp/shmem.fh"

INTEGER len, pe

CALL SHMEM_CHARACTER_GET(target, source, len, pe)

CALL SHMEM_COMPLEX_GET(target, source, len, pe)

CALL SHMEM_DOUBLE_GET(target, source, len, pe)

CALL SHMEM_GET4(target, source, len, pe)

CALL SHMEM_GET8(target, source, len, pe)

CALL SHMEM_GET32(target, source, len, pe)

CALL SHMEM_GET64(target, source, len, pe)

CALL SHMEM_GET128(target, source, len, pe)

CALL SHMEM_GETMEM(target, source, len, pe)

CALL SHMEM_INTEGER_GET(target, source, len, pe)

CALL SHMEM_LOGICAL_GET(target, source, len, pe)

CALL SHMEM_REAL_GET(target, source, len, pe)

✨ DESCRIPTION ✨

so here's the tea ☕ — the shmem_get routines transfer nelems elements of the data object sitting at address source on the remote PE pe, over to the data object at address target on the local PE. and important: these routines return after the data has been copied to address target on the local PE. no dangling, no "we'll do it later". it's done. periodt. 💅

the arguments, one by one

  • target — the local data object that's getting updated. glow-up incoming 💖
  • source — the data object on the PE identified by pe that holds the data to be copied. and no cap: this data object must be remotely accessible.
  • len — number of elements in the target and source arrays. len must be of type integer. if you're in Fortran-land, it must be a constant, variable, or array element of default integer type.
  • pe — the PE number of the remote PE. pe must be of type integer. and same deal for Fortran: it must be a constant, variable, or array element of default integer type.

the typing constraints (aka the dress code) 👑

the target and source data objects have to conform to typing constraints, and here's the list, bestie:

  • shmem_getmem — Fortran: any noncharacter type. C: any data type. and len is scaled in bytes.
  • shmem_get4, shmem_get32 — any noncharacter type that has a storage size equal to 32 bits.
  • shmem_get8, shmem_get64 — any noncharacter type that has a storage size equal to 64 bits.
  • shmem_get128 — any noncharacter type that has a storage size equal to 128 bits.
  • shmem_short_get — elements of type short.
  • shmem_int_get — elements of type int.
  • shmem_long_get — elements of type long.
  • shmem_longlong_get — elements of type long long.
  • shmem_float_get — elements of type float.
  • shmem_double_get — elements of type double.
  • shmem_longdouble_get — elements of type long double.
  • SHMEM_CHARACTER_GET — elements of type character. len is the number of characters to transfer. and get this: the actual character lengths of the source and target variables are ignored 🙈.
  • SHMEM_COMPLEX_GET — elements of type complex of default size.
  • SHMEM_DOUBLE_GET — (Fortran) elements of type double precision.
  • SHMEM_INTEGER_GET — elements of type integer.
  • SHMEM_LOGICAL_GET — elements of type logical.
  • SHMEM_REAL_GET — elements of type real.

if you're rolling with Fortran, data types must be of default size. so like, a real variable needs to be declared as REAL, REAL*4, or REAL(KIND=4). no improvising, bestie. 🦋

📝 NOTES 📝

head over to intro_shmem(3) if you want the actual definition of the term remotely accessible — that's where it lives, and yes, it matters here. iykyk. 💀

🌸 EXAMPLES 🌸

okay here's a cute little Fortran moment to make it click:

PROGRAM REDUCTION
  REAL VALUES, SUM
  COMMON /C/ VALUES
  REAL WORK

  CALL START_PES(0) ! ALLOW ANY NUMBER OF PES
  VALUES = MY_PE() ! INITIALIZE IT TO SOMETHING
  CALL SHMEM_BARRIER_ALL
  SUM = 0.0
  DO I = 0,NUM_PES()-1
    CALL SHMEM_REAL_GET(WORK, VALUES, 1, I)
    SUM = SUM + WORK
  ENDDO
  PRINT *, 'PE ', MY_PE(), ' COMPUTED SUM=', SUM
  CALL SHMEM_BARRIER_ALL
END

it's giving reduction, it's giving main character energy, it's giving sum. 🌈

see also 🎀

Copyright 2003-2026, The Open MPI Community.

okay that's the whole page bestie, you're officially fluent 💜 this was the SHMEM_LONGLONG_GET(3) page from Open MPI, and the version/date stamp on this one is Sep 10, 2026. go forth and get that data, you're gonna slay ✨🫶

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