splinter_get_raw_ptr

`splinter_get_raw_ptr` Splinter API Reference

The purpose of splinter_get_raw_ptr is to return a direct, read-only pointer into shared memory for a key's value, along with its length and the epoch at lookup time.

Forward Declaration & Use

const void *splinter_get_raw_ptr(const char *key, size_t *out_sz, uint64_t *out_epoch) <splinter.h>

size_t sz = 0;
uint64_t e1 = 0;
const void *p = splinter_get_raw_ptr("mykey", &sz, &e1);
if (p && !(e1 & 1)) {
    /* ... consume up to sz bytes ... */
    if (splinter_get_epoch("mykey") != e1) {
        /* torn read — discard and retry */
    }
}

Return & Rationale

Return Behavior: Returns a const pointer to the value data in shared memory, or NULL if the key is not found. out_sz receives the value length and out_epoch the epoch at lookup.

Errno Behavior: None.

Rationale (Or None): The pointer is live: another process can change or zero the memory between receiving and dereferencing it, so it must be paired with epoch verification and never held across a yield or sleep. Bytes beyond out_sz may be stale (see the mop modes), since raw access bypasses val_len checking.