SHMEM_LONGDOUBLE_PUT_NBI(3)

🎀 SHMEM_LONGDOUBLE_PUT_NBI(3) 🎀

okay bestie come CLOSE, this is a page from the Open MPI manual, section 3, and it's literally the blueprint for all the nonblocking put routines. Sending data from your memory to someone else's PE and then just... moving on with your life? it's giving main character energy ngl 💅

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✨ NAME ✨

so here's the whole friend group, no cap, every single one of them:

• shmem_putmem_nbi(3)
• shmem_char_put_nbi(3)
• shmem_short_put_nbi(3)
• shmem_int_put_nbi(3)
• shmem_long_put_nbi(3)
• shmem_longlong_put_nbi(3)
• shmem_float_put_nbi(3)
• shmem_double_put_nbi(3)
• shmem_longdouble_put_nbi(3)
• shmem_put8_nbi(3)
• shmem_put16_nbi(3)
• shmem_put32_nbi(3)
• shmem_put64_nbi(3)
• shmem_put128_nbi(3)

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

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🌈 SYNOPSIS 🌈

C or C++:

#include <mpp/shmem.h>

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

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

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

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

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

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

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

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

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

void shmem_put8(void *dest, const void *source,
  size_t nelems, int pe)

void shmem_put16(void *dest, const void *source,
  size_t nelems, int pe)

void shmem_put32(void *dest, const void *source,
  size_t nelems, int pe)

void shmem_put64(void *dest, const void *source,
  size_t nelems, int pe)

void shmem_put128(void *dest, const void *source,
  size_t nelems, int pe)

(yes I typed those exactly as they came, don't come for me 🙈)

Fortran:

INCLUDE "mpp/shmem.fh"

INTEGER nelems, pe

CALL SHMEM_PUTMEM_NBI(dest, source, nelems, pe)

CALL SHMEM_CHARACTER_PUT_NBI(dest, source, nelems, pe)

CALL SHMEM_COMPLEX_PUT_NBI(dest, source, nelems, pe)

CALL SHMEM_DOUBLE_PUT_NBI(dest, source, nelems, pe)

CALL SHMEM_INTEGER_PUT_NBI(dest, source, nelems, pe)

CALL SHMEM_LOGICAL_PUT_NBI(dest, source, nelems, pe)

CALL SHMEM_REAL_PUT_NBI(dest, source, nelems, pe)

CALL SHMEM_PUT4_NBI(dest, source, nelems, pe)

CALL SHMEM_PUT8_NBI(dest, source, nelems, pe)

CALL SHMEM_PUT32_NBI(dest, source, nelems, pe)

CALL SHMEM_PUT64_NBI(dest, source, nelems, pe)

CALL SHMEM_PUT128_NBI(dest, source, nelems, pe)

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💖 DESCRIPTION 💖

okay so the whole vibe here: the routines return after posting the operation. that's it. they don't wait around for the data to land, they just post it and dip 🏃‍♀️💨

the operation is considered complete after a subsequent call to shmem_quiet. so at the completion of shmem_quiet, the data has been copied into the dest array on the destination PE. iconic.

but here's the messy part 🙈 — the delivery of data words into the data object on the destination PE may occur in any order. and even more chaotic: two successive put routines may deliver data out of order unless a call to shmem_fence is introduced between the two calls. so if order matters to you, bestie, fence it. no cap.

🍓 the arguments, one by one

• dest — the data object to be updated on the remote PE. and lowkey important: this data object must be remotely accessible.
• source — the data object holding the data that's getting copied.
• nelems — number of elements in the dest and source arrays. for C, nelems must be of type size_t. for Fortran, 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. for Fortran, it must be a constant, variable, or array element of default integer type.

also, if you're in Fortran, data types must be of default size. like, a real variable has to be declared as REAL, REAL*4, or REAL(KIND=4). no weird sizes, we're keeping it standard ✨

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🧚 NOTES 🧚

if you're wondering what "remotely accessible" even means (fair question, bestie), go read intro_shmem(3) — it's got the definition. iykyk.

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👑 EXAMPLES 👑

here's a cute little C situation:

#include <stdio.h>
#include <mpp/shmem.h>

main()
{
  long source[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
  static long target[10];
  shmem_init();

  if (shmem_my_pe() == 0) {
    /* put 10 words into target on PE 1 */
    shmem_long_put_nbi(target, source, 10, 1);
    shmem_quiet();
  }
  shmem_barrier_all();  /* sync sender and receiver */
  if (shmem_my_pe() == 1)
    shmem_udcflush();  /* not required on Altix systems */
  printf("target[0] on PE %d is %d\n", shmem_my_pe(), target[0]);
}

look at shmem_quiet() doing the heavy lifting right after the put — that's the moment the data actually lands 💅

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 the Open MPI manual's SHMEM_LONGDOUBLE_PUT_NBI(3) page, dated Sep 10, 2026, and it ate, fr fr. go forth and put your long doubles nonblockingly ✨🦋💜