UnsatisfiedLinkError when run System.loadLibrary

Question

I am using pjsip library through android ndk. I used Android NDK 16 to compile pjsip. One user (HTC One, Android 5.0.2) faced a lot of crashes while trying to start our project. This is the error:

 Fatal Exception: java.lang.UnsatisfiedLinkError
dlopen failed: cannot locate symbol "stdin" referenced by "libpjsua2.so"...
... .PjSipApp.<clinit>

In the project we have .so-files for 4 abis, as stated in google android ndk official docs: arm64-v8a, armeabi-v7a, x86, x86_64. Here is how I load libraries in code:

public class PjSipApp {
    private static final String TAG = "Pjsua-PjSipApp";

    static {
        try {
            System.loadLibrary("openh264");
            System.loadLibrary("yuv");
        } catch (UnsatisfiedLinkError ignore) {
        }
        System.loadLibrary("pjsua2");
        Log.v(TAG, "LibraryLoaded");
    }...

So System.loadLibrary("pjsua2"); throws this UnsatisfiedLinkError. Maybe anyone knows, what is the reason for this?

Answer 1

You probably compiled binaries with a higher API Level.

This is how they are defined in stdio.h

#if __ANDROID_API__ >= 23
extern FILE* stdin __INTRODUCED_IN(23);
extern FILE* stdout __INTRODUCED_IN(23);
extern FILE* stderr __INTRODUCED_IN(23);
/* C99 and earlier plus current C++ standards say these must be macros. */
#define stdin stdin
#define stdout stdout
#define stderr stderr
#else
/* Before M the actual symbols for stdin and friends had different names. */
extern FILE __sF[] __REMOVED_IN(23);
#define stdin (&__sF[0])
#define stdout (&__sF[1])
#define stderr (&__sF[2])
#endif

So, if you built for API level >= 23, the symbol will resolve to File* stdin which doesn't exist in API < 23. I'd suggest to reduce the API level.