How to convert jbyteArray to native char* in jni?

Question

I am trying to convert a jbyteArray to native c string (char*) in jni? Unfortunately I can\'t find any documentation on how to do that. I\'m invoking a java function with th

Answer 1

I believe you would use GetByteArrayElements and ReleaseByteArrayElements. Something like:

boolean isCopy;
jbyte* b = GetByteArrayElements(env, arr, &isCopy);

You should be able to cast b to char* at this point in order to access the data in the array. Note that this may create a copy of the data, so you'll want to make sure to release the memory using ReleaseByteArrayElements:

ReleaseByteArrayElements(env, arr, b, 0);

The last parameter is a mode indicating how changes to b should be handled. 0 indicates that the values are copied back to arr. If you don't want to copy the data back to arr, use JNI_ABORT instead.

For more details see the JNI Reference.