How to print log in android c++ file?

Question

I added

#define LOG_NDEBUG 0
#define LOG_TAG "StagefrightMediaScanner"
#include <utils/Log.h>

in the libstagefright/StagefrightMediaScanner.cpp

but can not print anything using LOGV and LOGE, does any other things can I need to do?

@Lucifer No, I am using android 4.0 source code to debug the framework's issue. — Victor S, Aug 28 '12 at 04:00
Possible duplicate of [What is the Log API to call from an Android JNI program?](https://stackoverflow.com/questions/5465941/what-is-the-log-api-to-call-from-an-android-jni-program) — Ciro Santilli Путлер Капут 六四事, Nov 06 '17 at 09:46

score 47 · Accepted Answer · edited May 18 '22 at 07:16

47

You can use the following code to get Log

  __android_log_print(ANDROID_LOG_ERROR, "TRACKERS", "%s", Str);

and add the following header file

#include <android/log.h>

Additional docs are here: https://developer.android.com/ndk/reference/group/logging

edited May 18 '22 at 07:16

JoshuaMulliken

15
5

answered Dec 21 '12 at 07:01

Usman Kurd

8,335
7
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what is Str in this case? Is it a variable, what will be its value – Shirish Herwade Sep 10 '14 at 11:49
__android_log_write() – kinORnirvana Jan 17 '17 at 11:19
Also need to modify Android.mk, add "LOCAL_LDLIBS :=-llog" – franny zhao Apr 25 '19 at 05:41

score 2 · Answer 2 · edited Apr 30 '15 at 07:10

You can check frameworks/av/media/libstagefright/Android.mk, whether there is

 LOCAL_SHARED_LIBRARIES += liblog

in it.

Then, under frameworks/av/media/libstagefright/

$ mm

$ adb push $OUT/system/lib/libstagefright.so /system/lib/ 

$ adb shell killall mediaserver

Then reboot your phone or am start a MEDIA_MOUNTED intent, MediaScanner will work, and the logs you just added(either ALOGE/ALOGV or LOGE/LOGV) should be shown.

score 0 · Answer 3 · answered Dec 21 '12 at 06:46

0

No you have done right. Just check it whether you are using ALOGV() which is similar to printf(),if you want to print a integer with a log then you can write like this :" ALOGV("Integer is %d",integer);".

answered Dec 21 '12 at 06:46

Tarun Chawla

453
4
14

How to print log in android c++ file?

3 Answers3