SHMEM_GETMEM_NBI(3)

💖 SHMEM_GETMEM_NBI(3) 💖

okay bestie so this is a page from Open MPI, and it's literally all about the nonblocking get routines — like, one big happy family of them. Gather round 🫶

✨ NAME ✨

Here's the whole squad (yes, every single one, no skipping, I see you):

• shmem_getmem_nbi(3)
• shmem_char_get_nbi(3)
• shmem_short_get_nbi(3)
• shmem_int_get_nbi(3)
• shmem_long_get_nbi(3)
• shmem_longlong_get_nbi(3)
• shmem_float_get_nbi(3)
• shmem_double_get_nbi(3)
• shmem_longdouble_get_nbi(3)
• shmem_get8_nbi(3)
• shmem_get16_nbi(3)
• shmem_get32_nbi(3)
• shmem_get64_nbi(3)
• shmem_get128_nbi(3)

and what do they all do? The nonblocking get routines provide a method for copying data from a contiguous remote data object on the specified PE to the local data object. periodt. 💅

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🌈 SYNOPSIS 🌈

C or C++ 🌸

#include <mpp/shmem.h>

void shmem_getmem_nbi(void *dest, const void *source,
  size_t nelems, int pe)

void shmem_char_get(char *dest, const char *source,
  size_t nelems, int pe)

void shmem_short_get(short *dest, const short *source,
  size_t nelems, int pe)

void shmem_int_get(int *dest, const int *source,
  size_t nelems, int pe)

void shmem_long_get(long *dest, const long *source,
  size_t nelems, int pe)

void shmem_longlong_get(long long *dest, const long long *source,
  size_t nelems, int pe)

void shmem_float_get(float *dest, const float *source,
  size_t nelems, int pe)

void shmem_double_get(double *dest, const double *source,
  size_t nelems, int pe)

void shmem_longdouble_get(long double *dest, const long double *source,
  size_t nelems, int pe)

void shmem_get8(void *dest, const void *source,
  size_t nelems, int pe)

void shmem_get16(void *dest, const void *source,
  size_t nelems, int pe)

void shmem_get32(void *dest, const void *source,
  size_t nelems, int pe)

void shmem_get64(void *dest, const void *source,
  size_t nelems, int pe)

void shmem_get128(void *dest, const void *source,
  size_t nelems, int pe)

Fortran 🦋

INCLUDE "mpp/shmem.fh"

INTEGER nelems, pe

CALL SHMEM_GETMEM_NBI(dest, source, nelems, pe)

CALL SHMEM_CHARACTER_GET_NBI(dest, source, nelems, pe)

CALL SHMEM_COMPLEX_GET_NBI(dest, source, nelems, pe)

CALL SHMEM_DOUBLE_GET_NBI(dest, source, nelems, pe)

CALL SHMEM_INTEGER_GET_NBI(dest, source, nelems, pe)

CALL SHMEM_LOGICAL_GET_NBI(dest, source, nelems, pe)

CALL SHMEM_REAL_GET_NBI(dest, source, nelems, pe)

CALL SHMEM_GET4_NBI(dest, source, nelems, pe)

CALL SHMEM_GET8_NBI(dest, source, nelems, pe)

CALL SHMEM_GET32_NBI(dest, source, nelems, pe)

CALL SHMEM_GET64_NBI(dest, source, nelems, pe)

CALL SHMEM_GET128_NBI(dest, source, nelems, pe)

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🎀 DESCRIPTION 🎀

So the get routines are giving "copy a contiguous symmetric data object from a different PE into a contiguous data object on the local PE" ✨. The plot twist? These routines return right after posting the operation. Like, they said "k, sent, bye 👋".

The operation is considered complete after a subsequent call to shmem_quiet. At the completion of shmem_quiet, the data has been delivered to the dest array on the local PE. no cap, that's the whole deal.

The arguments, babes:

• dest — Local data object to be updated. 💖
• source — Data object on the PE identified by pe that contains the data to be copied. This data object must be remotely accessible. important!! 🔥
• nelems — 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.

okay and if you're 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). don't get cute with it 💀

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📝 NOTES 📝

See intro_shmem(3) for a definition of the term remotely accessible. iykyk 🌈

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⭐ EXAMPLES ⭐

Consider this simple example for Fortran. slay, it's a whole reduction:

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_NBI(WORK, VALUES, 1, I)
    CALL SHMEM_QUIET                ! wait for delivery
    SUM = SUM + WORK
  ENDDO
  PRINT *, 'PE ', MY_PE(), ' COMPUTED SUM=', SUM
  CALL SHMEM_BARRIER_ALL
END

🦄 See also

intro_shmem(3) shmem_quiet(3)

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Copyright 2003-2026, The Open MPI Community

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and that's the whole page, bestie!! 🫶✨ this was Open MPI, SHMEM_GETMEM_NBI(3), dated Sep 10, 2026 — go forth and nonblocking-get, you main character 👑💜