On 08/17/2018 05:12 PM, Volker Simonis wrote:
> The offending code in Console_md.c looks as follows:
>
> #define ECHO 8
>
> JNIEXPORT jboolean JNICALL
> Java_java_io_Console_echo(...) {
>
> jboolean old;
> ...
> old = (tio.c_lflag & ECHO);
> ...
> return old;
> }
>
> The intention of this code is to return "true" if the ECHO flag was
> set but it really returns the value of ECHO (which is defined as '8'
> in a system header).
>
> The question now is, if a Java SE compatible VM guarantees that any
> arbitrary, non-zero valued jboolean will be interpreted as "JNI_TRUE"
> and only a zero valued jboolean will be interpreted as "JNI_FALSE"?
>
> Or, the other way round, is the normalization performed by the HotSpot
> result handlers necessary (i.e. enforced by the specification) or just
> a convenience to fix broken code like the above from Console.echo()?
I think this is intentional aftermath of boolean value normalization:
https://bugs.openjdk.java.net/browse/JDK-8161720
So, Java_java_io_Console_echo looks broken and needs to be fixed, by e.g.:
- old = (tio.c_lflag & ECHO);
+ old = (tio.c_lflag & ECHO) != 0;
Thanks,
-Aleksey
