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/*--------------------------------------------------------------------------
*
* test_dsm_registry.c
* Test the dynamic shared memory registry.
*
* Copyright (c) 2024-2025, PostgreSQL Global Development Group
*
* IDENTIFICATION
* src/test/modules/test_dsm_registry/test_dsm_registry.c
*
* -------------------------------------------------------------------------
*/
#include "postgres.h"
#include "fmgr.h"
#include "storage/dsm_registry.h"
#include "storage/lwlock.h"
PG_MODULE_MAGIC;
typedef struct TestDSMRegistryStruct
{
int val;
LWLock lck;
} TestDSMRegistryStruct;
static TestDSMRegistryStruct *tdr_state;
static void
tdr_init_shmem(void *ptr)
{
TestDSMRegistryStruct *state = (TestDSMRegistryStruct *) ptr;
LWLockInitialize(&state->lck, LWLockNewTrancheId());
state->val = 0;
}
static void
tdr_attach_shmem(void)
{
bool found;
tdr_state = GetNamedDSMSegment("test_dsm_registry",
sizeof(TestDSMRegistryStruct),
tdr_init_shmem,
&found);
LWLockRegisterTranche(tdr_state->lck.tranche, "test_dsm_registry");
}
PG_FUNCTION_INFO_V1(set_val_in_shmem);
Datum
set_val_in_shmem(PG_FUNCTION_ARGS)
{
tdr_attach_shmem();
LWLockAcquire(&tdr_state->lck, LW_EXCLUSIVE);
tdr_state->val = PG_GETARG_UINT32(0);
LWLockRelease(&tdr_state->lck);
PG_RETURN_VOID();
}
PG_FUNCTION_INFO_V1(get_val_in_shmem);
Datum
get_val_in_shmem(PG_FUNCTION_ARGS)
{
int ret;
tdr_attach_shmem();
LWLockAcquire(&tdr_state->lck, LW_SHARED);
ret = tdr_state->val;
LWLockRelease(&tdr_state->lck);
PG_RETURN_UINT32(ret);
}
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