Re: POC: make mxidoff 64 bits

On 30/12/2025 03:49, zengman wrote:
> Hi，
>
> I'm currently looking into the `SlruReadSwitchPageSlow` function and have a question regarding the expression `&state->buf.data + bytes_read` —
> I suspect the ampersand (&) here might be misused. Would you be able to help me verify this?
>
> ```
> while (bytes_read < BLCKSZ)
> {
> ssize_t rc;
>
> rc = pg_pread(state->fd,
> &state->buf.data + bytes_read,
> BLCKSZ - bytes_read,
> offset);
> if (rc < 0)
> {
> if (errno == EINTR)
> continue;
> pg_fatal("could not read file \"%s\": %m", state->fn);
> }
> if (rc == 0)
> {
> /* unexpected EOF */
> pg_log(PG_WARNING, "unexpected EOF reading file \"%s\" at offset %u, reading as zeros",
> state->fn, (unsigned int) offset);
> memset(&state->buf.data + bytes_read, 0, BLCKSZ - bytes_read);
> break;
> }
> bytes_read += rc;
> offset += rc;
> }
> ```
>
> ```
> rc = pg_pread(state->fd,
> &state->buf.data + bytes_read,
> BLCKSZ - bytes_read,
> offset);
> memset(&state->buf.data + bytes_read, 0, BLCKSZ - bytes_read);
> ```

Yes, you're right. Good catch! Committed the fix, thanks.

- Heikki