Question

I’m developing an Android application with native code.

I don’t know how to debug a shared library so I decided to log values from a pointer to LogCat.

I have this C++ code:

extern GLfloat* vertPos;

// More code here:
...

int i = 0;
for(i = 0; i < numVertices; i++)
{
      __android_log_print(ANDROID_LOG_VERBOSE, "initRendering-Vertices", "%d, %f", i, vertPos[i]);
}

numVertices is equal to 2472 elements.

I’m getting something like that at LogCat:

12-11 08:17:35.354: VERBOSE/initRendering-Vertices(900): i = 614, value = 3.246999
12-11 08:17:35.354: VERBOSE/initRendering-Vertices(900): i = 924, value = -8.000200

I’ve lost 310 elements.

Is there any other way to see all pointer’s elements?

Thanks.

Answer 1

The Android log implementation uses a 64KB circular buffer in the kernel. If you manage to write data to the log faster than “logcat” can read it out, you will start losing lines. Since logcat has to wait on adb to send output over USB to your workstation, it’s not that hard to outrun it.

Use fopen to create a file called /sdcard/debug.txt, change the __android_log_print() to fprintf(), and then “adb pull” the output off after the run completes. That will ensure nothing is dropped.