SHMEM_PUT32(3)

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version 26.9 · 7 versions
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💖 SHMEM_PUT32(3) 💖 — the Open MPI girlies of put, manual section 3 ✨

okay so this is the Open MPI manual page, section 3, and it covers a whole squad of routines — like eighteen of them, bestie, they all showed up to the group chat:

and what do they do? they transfer data to a specified processing element (PE) 🫶 that's the whole assignment. iconic behavior, no cap.

✨ SYNOPSIS ✨

C or C++:

#include <mpp/shmem.h>

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

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

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

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

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

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

void shmem_put32(void *target, const void *source, size_t len,
  int pe)

void shmem_put64(void *target, const void *source, size_t len,
  int pe)

void shmem_put128(void *target, const void *source, size_t len,
  int pe)

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

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

Fortran:

INCLUDE "mpp/shmem.fh"

INTEGER len, pe

CALL SHMEM_CHARACTER_PUT(target, source, len, pe)

CALL SHMEM_COMPLEX_PUT(target, source, len, pe)

CALL SHMEM_DOUBLE_PUT(target, source, len, pe)

CALL SHMEM_INTEGER_PUT(target, source, len, pe)

CALL SHMEM_LOGICAL_PUT(target, source, len, pe)

CALL SHMEM_PUT(target, source, len, pe)

CALL SHMEM_PUT4(target, source, len, pe)

CALL SHMEM_PUT8(target, source, len, pe)

CALL SHMEM_PUT32(target, source, len, pe)

CALL SHMEM_PUT64(target, source, len, pe)

CALL SHMEM_PUT128(target, source, len, pe)

CALL SHMEM_PUTMEM(target, source, len, pe)

CALL SHMEM_REAL_PUT(target, source, len, pe)

🌸 DESCRIPTION 🌸

so here's the tea ☕ — these routines transfer nelems elements of the data object at address source on the calling PE, over to the data object at address target on the remote PE pe. and the little plot twist: these routines start the remote transfer and may return before the data is delivered to the remote PE. so yeah, it's giving "sent, not necessarily delivered" energy 😭 don't assume it landed just because the function came back.

the delivery of data into the data object on the destination PE from different put calls may occur in any order. because of this, two successive put operations may deliver data out of order — unless you slip a call to shmem_fence(3) in between the two calls. that's the whole trick, bestie. fence between them or accept the chaos 💀

🎀 The arguments (meet the cast)

  • target — data object to be updated on the remote PE. this one must be remotely accessible. non-negotiable, it's literally the main character.
  • source — data object containing the data to be copied.
  • len — number of elements in the target and source arrays. len must be of type integer. if you're 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're using Fortran, it must be a constant, variable, or array element of default integer type.

🦋 The typing constraints (vibe check for your data types)

the target and source data objects must conform to certain typing constraints, which are as follows:

  • shmem_putmem:** Fortran: any noncharacter type. C: any data type. len is scaled in bytes.
  • shmem_put4, shmem_put32:** any noncharacter type that has a storage size equal to 32 bits.
  • shmem_put8, shmem_put64:** any noncharacter type that has a storage size equal to 64 bits.
  • shmem_put128:** any noncharacter type that has a storage size equal to 128 bits.
  • shmem_short_put:** elements of type short.
  • shmem_int_put:** elements of type int.
  • shmem_long_put:** elements of type long.
  • shmem_longlong_put:** elements of type long long.
  • shmem_float_put:** elements of type float.
  • shmem_double_put:** elements of type double.
  • shmem_longdouble_put:** elements of type long double.
  • SHMEM_CHARACTER_PUT:** elements of type character. len is the number of characters to transfer. the actual character lengths of the source and target variables are ignored 🙈
  • SHMEM_COMPLEX_PUT:** elements of type complex of default size.
  • SHMEM_DOUBLE_PUT:** (Fortran) elements of type double precision.
  • SHMEM_INTEGER_PUT:** elements of type integer.
  • SHMEM_LOGICAL_PUT:** elements of type logical.
  • SHMEM_REAL_PUT:** elements of type real.
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 be out here declaring whatever, the default-size rule is the rule ✨

🔥 EXAMPLES 🔥

the following shmem_put example is for C/C++ programs:

#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(target, source, 10, 1);
  }
  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 that little shmem_barrier_all() doing the sync between sender and receiver — we love a coordinated moment 🫶

👑 SEE ALSO 👑

2003-2026, The Open MPI Community

and that's the page, bestie! slay 💅 this lil sign-off is brought to you by Open MPI, dated May 14, 2026 — go put some data on a remote PE and make it iconic ✨🎀🦋

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