Other Aliasshmem_int_wait3, shmem_int_wait3_until, shmem_int4_wait3_until, shmem_int8_wait3, shmem_int8_wait3_until, shmem_long_wait3, shmem_long_wait3_until, shmem_longlong_wait3
C or C++:
void shmem_int_wait(int *var, int value);
void shmem_int_wait_until(int *var, int cond, int value);
void shmem_long_wait(long *var, long value);
void shmem_long_wait_until(long *var, int cond, long value);
void shmem_longlong_wait(long long *var, long long value);
void shmem_longlong_wait_until(long long *var, int cond,
long long value);
void shmem_short_wait(short *var, short value);
void shmem_short_wait_until(short *var, int cond,
void shmem_wait(long *ivar, long cmp_value);
void shmem_wait_until(long *ivar, int cmp, long value);
INCLUDE "mpp/shmem.fh" CALL SHMEM_INT4_WAIT(ivar, cmp_value) CALL SHMEM_INT4_WAIT_UNTIL(ivar, cmp, cmp_value) CALL SHMEM_INT8_WAIT(ivar, cmp_value) CALL SHMEM_INT8_WAIT_UNTIL(ivar, cmp, cmp_value) CALL SHMEM_WAIT(ivar, cmp_value) CALL SHMEM_WAIT_UNTIL(ivar, cmp, cmp_value)
shmem_wait and shmem_wait_until wait for ivar to be changed by a remote write or atomic swap issued by a different processor. These routines can be used for point-to- point directed synchronization. A call to shmem_wait does not return until some other processor writes a value, not equal to cmp_value, into ivar on the waiting processor. A call to shmem_wait_until does not return until some other processor changes ivar to satisfy the condition implied by cmp and cmp_value. This mechanism is useful when a processor needs to tell another processor that it has completed some action.
The arguments are as follows:
- The remotely accessible integer data object to be updated on the remote PE. If you are using C/C++, the type of target should match that implied in the SYNOPSIS section. If you are using the Fortran compiler, it must be of type integer with an element size of 4 bytes for SHMEM_INT4_ADD and 8 bytes for SHMEM_INT8_ADD.
- The value to be atomically added to target. If you are using C/C++, the type of value should match that implied in the SYNOPSIS section. If you are using Fortran, it must be of type integer with an element size of target.
- An integer that indicates the PE number upon which target is to be updated. If you are using Fortran, it must be a default integer value.
A remotely accessible integer variable that is being updated by another PE. If you
are using C/C++, the type of ivar should match that implied in the SYNOPSIS section. If you
are using Fortran, ivar must be a specific sized integer type according to
the function being called, as follows:
- shmem_wait, shmem_wait_until: default INTEGER
- shmem_int4_wait, shmem_int4_wait_until: INTEGER*4
- shmem_int8_wait, shmem_int8_wait_until: INTEGER*8
The compare operator that compares ivar with cmp_value. cmp must be of type
integer. If you are using Fortran, it must be of default kind. If you are using C/C++, the type
of cmp should match that implied in the SYNOPSIS section. The following cmp values are
- Not equal
- Greater than
- Less than or equal to
- Less than
- Greater than or equal to
- cmp_value must be of type integer. If you are using C/C++, the type of cmp_value should match thatimplied in the SYNOPSIS section. If you are using Fortran, cmp_value must be an integer of the same size and kind as ivar. The shmem_wait routines return when ivar is no longer equal to cmp_value. The shmem_wait_until routines return when the compare condition is true. The compare condition is defined by the ivar argument compared with the cmp_value using the comparison operator, cmp.
Example 1: The following call returns when variable ivar is not equal to 100:
INTEGER*8 IVAR CALL SHMEM_INT8_WAIT(IVAR, INT8(100))Example 2: The following call to SHMEM_INT8_WAIT_UNTIL is equivalent to the call to SHMEM_INT8_WAIT in example 1:
INTEGER*8 IVAR CALL SHMEM_INT8_WAIT_UNTIL(IVAR, SHMEM_CMP_NE, INT8(100))Example 3: The following C/C++ call waits until the sign bit in ivar is set by a transfer from a remote PE:
int ivar; shmem_int_wait_until(&ivar, SHMEM_CMP_LT, 0);Example 4: The following Fortran example is in the context of a subroutine:
SUBROUTINE EXAMPLE() INTEGER FLAG_VAR COMMON/FLAG/FLAG_VAR . . . FLAG_VAR = FLAG_VALUE ! initialize the event variable . . . IF (FLAG_VAR .EQ. FLAG_VALUE) THEN CALL SHMEM_WAIT(FLAG_VAR, FLAG_VALUE) ENDIF FLAG_VAR = FLAG_VALUE ! reset the event variable for next time . . . END