Passing Integer arguments from Java function to JNI function returning garbage values?

Question

I am calling a JNI function with int values as parameters. I am sending width and height as 800 and 480. But when I try to print these values in the JNI function I am getting 1 and 0 instead of 800 and 480. Why I am getting wrong values in JNI?

My JNI function call is:

findSquare(sourceImage.getNativeObjAddr(),
                        imageTaken.getNativeObjAddr(), 1, width, height);

public native void findSquare(long matAddrRgba, long matAddrDescriptor,
        int draw, int width, int height);

And the JNI function is:

JNIEXPORT jint JNICALL 
Java_info_androidhive_androidcameraapi_CameraMainActivity_findSquare(
        JNIEnv*, jobject, jlong addrRgba, jlong addrDescriptor, jlong addrSrc,
        jlong addrDst, jint draw, jint width, jint height);

Hi there !! You seem to be around for quite long time. Please take care of the formatting of the post yourself. Thank you. :-) — Sourav Ghosh
– Sourav Ghosh, Commented Mar 31, 2015 at 9:52
It seems like arguments in prototype and call function doesn't match. What happened with addrSrc and addrDst? — Anto Jurković
– Anto Jurković, Commented Mar 31, 2015 at 9:54
They are not matching. You have (long, long, int, int, int) on the Java side and (jlong, jlong, jlong, jint, jint, jint) on the JNI side. Reconcile this. — user207421
– user207421, Commented Mar 31, 2015 at 10:14
Actually it's even worse than that. You have five parameters in Java and seven in JNI, not counting the JNIEnv* and the jobject. — user207421
– user207421, Commented Mar 31, 2015 at 11:47

user207421 · Accepted Answer · 2015-03-31 10:14:43Z

4

The android and native method signatures don't match.

Your Java native method should look like this:

// added addrSrc, addrDst which were missing.
public native void findSquare(long matAddrRgba, long matAddrDescriptor, 
                              long addrSrc, long addrDst, int draw, int width, 
                              int height);

edited Mar 31, 2015 at 10:14

user207421

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answered Mar 31, 2015 at 10:12

Gil Moshayof

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2 Comments

sravanalakshmi.sunkara Over a year ago

Iam getting Fatal signal 11 (SIGSEGV) at 0x00000004 (code=1) exception while calling native method? Could you please help me?

sravanalakshmi.sunkara Over a year ago

This exception will arise if we try to use a vector of size 0(in my case). I've missed 'length(>0)' check while using it with for loop.

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