How to redirect cout to logcat

Currently used way of redirection

Paste the following code somewhere in the runtime's .cpp files and invoke start_logger providing a name for the logger (paste in e.g. Runtime.cpp's Runtime::Init method). You should also include <unistd.h> Huge thanks to: https://codelab.wordpress.com/2014/11/03/how-to-use-standard-output-streams-for-logging-in-android-apps/

static int pfd[2];
static pthread_t thr;
static const char *tag = "myapp";

static void *thread_func(void*)
{
    ssize_t rdsz;
    char buf[128];
    while((rdsz = read(pfd[0], buf, sizeof buf - 1)) > 0) {
        if(buf[rdsz - 1] == '\n') --rdsz;
        buf[rdsz] = 0;  /* add null-terminator */
        __android_log_write(ANDROID_LOG_DEBUG, tag, buf);
    }
    return 0;
}

int start_logger(const char *app_name)
{
    tag = app_name;

    /* make stdout line-buffered and stderr unbuffered */
    setvbuf(stdout, 0, _IOLBF, 0);
    setvbuf(stderr, 0, _IONBF, 0);

    /* create the pipe and redirect stdout and stderr */
    pipe(pfd);
    dup2(pfd[1], 1);
    dup2(pfd[1], 2);

    /* spawn the logging thread */
    if(pthread_create(&thr, 0, thread_func, 0) == -1)
        return -1;
    pthread_detach(thr);
    return 0;
}

Additional notes

You may have in mind this library: https://sourceforge.net/p/pstreams/code/ci/master/tree/ Perhaps it could be useful in similar cases.