RFR: 8377707: [Linux Alpine] Build failure after JDK-8377368

[Yasumasa Suenaga]

On Fri, 13 Feb 2026 10:19:07 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

> On Linux Alpine, we get the following build error:
> 
> 
> libproc_impl.h:99:4: error: 'off64_t' does not name a type; did you mean 'off_t'?
>    99 | off64_t vdso_offset; // offset of vDSO in core
>       | ^~~~~~~
>       | off_t
> 
> 
> and 
> 
> 
> jdk/src/jdk.hotspot.agent/linux/native/libsaproc/ps_core.c:639:11: error: implicit declaration of function 'sendfile64'; did you mean 'sendfile'? [-Wimplicit-function-declaration]
>   639 | if (sendfile64(lib_fd, ph->core->core_fd, &ofs, ph->core->vdso_size) == -1) {
>       | ^~~~~~~~~~
>       | sendfile

I think it is better to keep to use `off64_t` and `sendfile64` because `off_t` is `signed int`.
https://man7.org/linux/man-pages/man3/off_t.3type.html
(but it wouldn't be a problem if we use `off_t` because vDSO is not so large, I believe)

IMHO it is better if we can use `#ifdef`.

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PR Review: https://git.openjdk.org/jdk/pull/29710#pullrequestreview-3807405992