Turn off console logging for specific objects

Question

It\'s some kind of annoying: Since I started using the MPMoviePlayerController the console is overfilled with information from MPAVController. Eg:

[MPAVCon         


        

Answer 1

I don't think such filtering is possible out of the box. But it's possible to redirect stderr (which is used by NSLog) into a pipe, read from that pipe in a background thread and then print messages that pass through the filter onto stdout (which is captured by the debugger as well). This code does the job:

int main(int argc, char *argv[])
{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^(void) {
        size_t const BUFFER_SIZE = 2048;

        // Create a pipe
        int pipe_in_out[2];
        if (pipe(pipe_in_out) == -1)
            return;

        // Connect the 'in' end of the pipe to the stderr
        if (dup2(pipe_in_out[1], STDERR_FILENO) == -1)
            return;

        char *buffer = malloc(BUFFER_SIZE);
        if (buffer == 0)
            return;

        for (;;)
        {
            // Read from the 'out' end of the pipe
            ssize_t bytes_read = read(pipe_in_out[0], buffer, BUFFER_SIZE);
            if (bytes_read <= 0)
                break;

            // Filter and print to stdout
            if (should_show(buffer)) // TODO: Apply filters here
                fwrite(buffer, 1, bytes_read, stdout);
        }

        free(buffer);
        close(pipe_in_out[1]);
    });

    // Rest of main
}

Please note that this code is quite simple and doesn't handle all corner cases. First of all it captures all stderr output and not just NSLog. Maybe this could be filtered out by checking against the content. NSLog output always starts with the date and time.

Second problem with this code is that it doesn't try to split/join strings it reads from the pipe. There's no guarantee that there will be one NSLog per read. They could be coming together or be too long and would be split. To handle this it would require additional processing of the data read from the pipe.

Anyway, for many practical purposes this should be enough.