How to display logs from .CPP file in LogCat?

[Atul Prakash]

Hello Friends,

I am using .CPP file in my Android Project using NDK. Is there any
function through which I can display any output from my .CPP file just
like System.out.println("Message"); or Log.d("Message"); in .java
files which is being displayed in LogCat as output message.

This technique of displaying output on LogCat will help me check the
program flow.

Is cout<<"Message" or printf("Message"); of C/C++ will work on .CPP
files which I am implementing through NDK? If yes then where can I get
these output messages i.e. either on LogCat or on Cygwin console or
somewhere else.

I have also tried to use:

#include <android/log.h>

In some method I have also written this, in order to print it in
LogCat, but I got no output.

__android_log_print(ANDROID_LOG_INFO, "This is my first log in
LogCat");
__android_log_print(ANDROID_LOG_INFO, "Tank", "resize w=%d h=%d", w,
h);

I have also added following line to Android.mk file:

LOCAL_LDLIBS := -lGLESv1_CM -ldl -llog

Please tell me what is missing in my .CPP code in order to display
Logs on LogCat.

Thanks in advance.

Atul Prakash Singh

[liuwg2005]

try to change 'ANDROID_LOG_INFO' to 'ANDROID_LOG_DEBUG'

 

 

2011-04-20

---

liuwg2005

---

发件人： Atul Prakash

发送时间： 2011-04-20  15:37:26

收件人： android-ndk

抄送：

主题： How to display logs from .CPP file in LogCat?

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[Atul Prakash]

Changing ANDROID_LOG_INFO to ANDROID_LOG_DEBUG didn't work.

I would also like to know about the number & type of arguments
__android_log_print() method takes as I am getting
error : too few arguments to function int __android_log_print(int ,
const *char, const *char, .. );

[Riasat Abir]

This worked for me: http://stackoverflow.com/questions/5459324/how-to-see-printf-lines-in-gdb

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[mic _]

>>I would also like to know about the number & type of arguments __android_log_print() method takes

int __android_log_print(int prio, const char *tag, const char *fmt, ...)

/Michael

[Atul Prakash]

Thanks everybody!!!! It worked.

On Apr 20, 1:42 pm, mic _ <micol...@gmail.com> wrote:
> >>I would also like to know about the number & type of arguments
>
> __android_log_print() method takes
>
> int __android_log_print(int prio, const char *tag, const char *fmt, ...)
>
> /Michael
>
>
>
>
>
>
>
> On Wed, Apr 20, 2011 at 10:11 AM, Riasat Abir <riasat.a...@gmail.com> wrote:
> > This worked for me:

> >http://stackoverflow.com/questions/5459324/how-to-see-printf-lines-in...

>
> > On Wed, Apr 20, 2011 at 2:09 PM, Atul Prakash <atul.prakas...@gmail.com>wrote:
>
> >> Changing ANDROID_LOG_INFO to ANDROID_LOG_DEBUG didn't work.
>
> >> I would also like to know about the number & type of arguments
> >> __android_log_print() method takes as I am getting
> >> error : too few arguments to function int __android_log_print(int ,
> >> const *char, const *char, .. );
>
> >> --
> >> You received this message because you are subscribed to the Google Groups
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> >> To post to this group, send email to andro...@googlegroups.com.
> >> To unsubscribe from this group, send email to
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> >>http://groups.google.com/group/android-ndk?hl=en.
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>

[Cherwoo Kim]

Hi, Atul.

Printing log to Logcat is quite easy.

Try to include the head file <utils/Log.h>, and use LOGE, LOGW, LOGD,
LOGI, LOGV functions to print Error, warning, debug, info, verbose
messages to logcat.

For example:

#define LOG_TAG XXX // its the tag u can see in the logcat.
#include <utils/Log.h>

...
...

LOGE("mmmmmm printing log %s,%d",__FILE__,__LINE__);// it's gonna be
printed in error level, with tag XXX

You can find similar use of LOG utils in android cpp source files.

Hope this helps.