SHMEM_LONGDOUBLE_GET(3)

💖 SHMEM_LONGDOUBLE_GET 💖 (3)

okay bestie, listen — this is an Open MPI man page, and it's the whole glow-up squad of shmem_get routines. They all do the same iconic thing (yank data off a remote PE and drop it locally) but each one is styled for a different data type. no cap. 💅

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🦋 NAME 🦋

Meet the whole friend group — every single one of these transfers data from a specified processing element (PE):

• shmem_character_get(3)
• shmem_complex_get(3)
• shmem_double_get(3)
• shmem_float_get(3)
• shmem_get4(3)
• shmem_get8(3)
• shmem_get32(3)
• shmem_get64(3)
• shmem_get128(3)
• shmem_getmem(3)
• shmem_int_get(3)
• shmem_integer_get(3)
• shmem_logical_get(3)
• shmem_long_get(3)
• shmem_longdouble_get(3)
• shmem_longlong_get(3)
• shmem_real_get(3)
• shmem_short_get(3)

and yes, they are all doing the exact same transfer-from-a-PE thing. one job, seventeen-ish outfits. periodt. 👑

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✨ SYNOPSIS ✨

🩵 C or C++

#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)

💜 Fortran

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)

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🌸 DESCRIPTION 🌸

so like, 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 the way that these routines return only after the data has been copied to address target on the local PE? that's the whole point, that's the moment. 🫶

🎀 the arguments (character study)

• target — the local data object that's getting updated. it's the one receiving. 💖
• source — the data object on the PE identified by pe that holds the data to be copied. this one must be remotely accessible. no exceptions bestie.
• len — number of elements in the target and source arrays. len must be of type integer. if you're in Fortran, it has to 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. Fortran besties: again, it must be a constant, variable, or array element of default integer type.

🧚 typing constraints (the vibe check)

the target and source data objects must conform to these, fr fr:

• shmem_getmem — Fortran: any noncharacter type. C: any data type. 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. the actual character lengths of the source and target variables are ignored, iykyk.
• 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.

⚠️ Fortran girlies listen up: data types must be of default size. like, a real variable has to be declared as REAL, REAL*4, or REAL(KIND=4). don't come in here with the custom sizes, that's not the move. 😭

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💅 NOTES 💅

if you wanna know what remotely accessible even means, go read intro_shmem(3). it's giving required reading. 📚

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🍓 EXAMPLES 🍓

okay here's a cute little Fortran moment, a whole reduction situation:

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

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👑 SEE ALSO 👑

go give these a lil read too, bestie:

• intro_shmem(3)
• shmem_put(3)
• shmem_iget(3)
• shmem_quiet(3)

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Copyright 2003-2026, The Open MPI Community. 💖

and that's the page, written Sep 10, 2026, straight from your Open MPI besties — mwah, slay, go fetch that data. ✨🦋🎀