App crashes at point where class method synthesized with CC_SYNTHESIZE is used

cocos2d-x C++
#1

I’m using this in my class:

CC_SYNTHESIZE(cocos2d::CCPoint, velocity_, Velocity);

And in my main scene class, where I’m using it, like this:

`float rx = (float)(arc4random() % 100)/100;
float ry = (float)(arc4random() % 100)/100;

//'a' is the object of a Sprite class of mine
a->setVelocity(ccp(rx,ry));
`

I’m getting
A/libc(14897): Fatal signal 11 (SIGSEGV) at 0x5d3145dc (code=2), thread 14911 (Thread-1500)
in Logcat.

#2

Could you please post the whole stack ? to see the error?

How do you know it crashes in this point? Which error do you get?