On Fri, 18 Aug 2023 01:24:20 GMT, Coleen Phillimore <cole...@openjdk.org> wrote:
>> I don't follow. The fields are int so cast them to jlong before returning
>> them. All the callers of these methods expect jlong so there can't be any
>> issue there.
>
> You don't need to cast from int to jlong. The callers of these methods
> expect int:
>
>
> src/hotspot/share/services/threadService.cpp:1103:55: warning: conversion
> from 'jlong' {aka 'long int'} to 'int' may change value [-Wconversion]
> 1103 | int init_size = ThreadService::get_live_thread_count();
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
>
>
> Changing int to jlong here, gets a new warning:
>
>
> src/hotspot/share/services/threadService.cpp:1104:54: warning: conversion
> from 'jlong' {aka 'long int'} to 'int' may change value [-Wconversion]
> 1104 | _threads_array = new GrowableArray<instanceHandle>(init_size);
> | ^~~~~~~~~
>
>
> If you look up in the header file, the field is an int. It makes sense to
> return an int:
>
>
> static volatile int _atomic_threads_count;
> static volatile int _atomic_daemon_threads_count;
>
>
> Correcting the types means returning a type that matches the declaration so
> that its consistent.
I'd missed the GrowableArray code - the other callers expect jlong/64-bit.
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PR Review Comment: https://git.openjdk.org/jdk/pull/15233#discussion_r1297911413
