Question

While debugging my native code I wrote these lines:

m_sock = socket(m_iAf, m_iType, m_iProtocol);
printf("errno = %d, %s\n", errno, strerror(errno));
printf("Hellowrold\n");

I created a socket, but when i execute this line, it’s returning negative.
So I have to find the error. But the printing of neither errno nor Helloworld is shown on the console.

How can I see the printed lines?

I am new with ndk-gdb, so need help please.

Thanks,
Riasat

Answer 1

Instead of printf you can use the android logging facility:

#include <android/log.h>

__android_log_print(ANDROID_LOG_INFO, "MYPROG", "errno = %d, %s", errno, strerror(errno));
__android_log_print(ANDROID_LOG_INFO, "MYPROG", "Hellowrold");

No need for the trailing “\n” here and these will show up in logcat. You need to link to the logging library too. In your Android.mk file, add the following:

LOCAL_LDLIBS := -llog