RFR(XS): 8198906: JDK-8196882 breaks VS2013 Win32 builds (original) (raw)

Thomas Stüfe thomas.stuefe at gmail.com
Fri Mar 2 06:34:11 UTC 2018

On Fri, Mar 2, 2018 at 2:45 AM, David Holmes <david.holmes at oracle.com> wrote:

On 2/03/2018 6:29 AM, Kim Barrett wrote:

Please review this change to fix a build failure on Win32 when using VS2013 (and likely earlier). In os::vsnprintf, cast the int result to sizet for comparison with the buffer size, after having verified the result is non-negative.

Seems harmless. I'm not sure why this failure doesn't occur with VS2013 Win64 builds. I'm a bit confused how a function that takes a parameter indicating the number of characters to write, and then returns the number of characters written, can use two different, and potentially different sized, types! On 64-bit sizet would be 64-bit but int is 32-bit, so how can you possibly always return the correct count? Granted it may not be a practical concern, but from a typing perspective this seems seriously messed up. Further sizet is unsigned so has twice the range of int - so even on 32-bit this doesn't make sense. Am I missing something?

One problem is that the result type must be signed to be able to represent error cases as well. So even if it were ssize_t it would not cover the whole range of the input size_t.

Thanks,

David

CR: https://bugs.openjdk.java.net/browse/JDK-8198906

Webrev: http://cr.openjdk.java.net/~kbarrett/8198906/open.00/ Testing: VS2013 Win64 still builds. I don't have access to Win32, but the change is pretty simple.

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