Is there a way/tool to enumerate all the C function prototypes (not sure if that's the right term) from the .h files in the NDK folder subdirectories (i.e. C:\android-ndk-r8b\platforms\android-9\arch-arm\usr\include) and produce something like a javadoc? The reason I'm asking is because we have a developer on our end who is trying to port his Windows code over to the android platform and before he begins to go forward with such an effort, he needs to know what API calls are supported so he can begin changing his code base to make it Android-NDK compliant. I've run across the following links in my search for an answer:
http://mobilepearls.com/labs/native-android-api/#c++
C:/android-ndk-r8b/docs/STABLE-APIS.html
C:/android-ndk-r8b/docs/CPLUSPLUS-SUPPORT.html
The right way to check if the code is compliant is to compile it and see what breaks. Win32 API surely would - there's even no point in checking if an NDK counterpart exists. The C/C++ RTL is a little more tricky - some functions have counterparts, some don't. But enumerating them all and matching by hand is, frankly, a waste of time. A compiler will do the same much faster.
For starters, let the code be Linux compliant. The minute differences between Android libs and Linux can usually be resolved incrementally. Note that you have a moving target here: platform-14 supports much more Linux headers than 9.
http://www.tenouk.com/Module000linuxnm3.html
can you use libs instead of .h files?
the link explains using 'nm' to dump symbols from libs
Related
I would like to use a shared library, that is compiled for arm64, on Android. I have my .so file inside a aarch64-linux-gnu folder, but for other libraries I have instead a aarch64-linux-android folder.
Please can these libraries compiled for aarch64-linux-gnu run on an arm64 Android device? What do these names stand for precisely? I know that aarch64 refers to the arm64 processor architecture but I don't know how the operating system is related here.
Thank you!
Android and ARM my have some libraries that are the same. Basically the SO file has to be able to find all the libraries it was linked against to run, and the versions need to match up so nothing breaks. This is risky, and it is generally safest to compile the entire program on your target machine. You can see if everything can be located/what is missing using:
ldd /path/to/file.so
this will give you a list of libraries and where the file thinks they are - or ??? if it can't find it. You need to double check and see if the results of this look OK.
Even if all dependencies are found, mismatch in versions or architecture will cause the program to break at run-time. You need to extensively test the use of the externally linked library and even then you may miss some cases that break your program. For this reason I would try and get the source code if possible, and re-compile everything on the target machine.
I need to compile libmysqlclient and librtlstr for Android (in fact I could find rtlsdr, but since I need mysqlclient the issue is still there).
I followed several guides but most of them present the instruction written here http://mortoray.com/2012/08/21/android-ndk-cross-compile-setup-libpng-and-freetype/
Anyway, the package I download did not contain any configure file so I don't know how to continue.
Because the purpose of this file should only be the creation of the makefile, maybe there is a way solve this.
So my questions are:
1) Is this the right approach? Are there others easier?
2) Does a general configure file exist so that I can download and use it?
3)If not, how does the makefile has to be written? This way I should be able to overcome the abscence of configure file
I need those libraries to port a c code (which needs them) to android building an executable that I'll run on my phone (so I already have the standalone toolchain from the NDK), if it helps
1) This is right approach (may be a little bit simplified, I'm using more steps to build) for libraries, which use automake. Much easier, if library uses Cmake (must contain CMakeLists.txt), because you need only NDK. Example: cmake -DANDROID_NDK=path/to/ndk -DCMAKE_TOOLCHAIN_FILE=$NDK/build/cmake/android.toolchain.cmake -DANDROID_ABI=armeabi-v7a -DANDROID_PLATFORM=android-21 ..
2) No, also you need provide additional files (for example, Makefile.in)
3) This libraries have to use one of tools such CMake, automake etc, just Makefile or project for some IDE. So, try to find out, what of this use your libraries
This is a compilation problem, specifically with referencing shared libraries with NDK.
I have the SDL2 + GLEW program running fine on my mac (obviously with a different makefile/build system), and I have it running fine on Android as well (so long as I don't use GLEW). But now I need to use GLEW, and can't find a straightforward reference for how/where/what the heck is going on with including libraries in the NDK.
Anyways- in my android-project folder, I have jni/src/Android.mk (which I assume is where I should be looking?)
There's a line with LOCAL_SHARED_LIBRARIES := SDL2 SDL2_image, and I assume that's the magic variable that I shlould add GLEW to? But what even is that? How does that know what GLEW even means? Should it be -lGLEW? (that last question is rhetorical- I've tried all of them and nothing works). I've even tried commenting out that line totally and get the same build error:
jni/src/src/main.cpp:8:21: fatal error: GL/glew.h: No such file or directory
#include <GL/glew.h>
I'm pretty much totally lost... does anyone have any resources I could look into?
Also, as a note, I'd also prefer an explanation regarding why/what is going on, as I'm sure I'll be including other stuff as I go on.
Edit:
As Drop pointed out below, this wasn't a linking problem- the compiler needed to know where to find GL/glew.h. So I added /usr/local/Cellar/glew/1.12.0/include to the LOCAL_C_INCLUDES := line, and that works. But now, there's an error compiling glew.h- GL/glu.h: No such file or directory.
So now,
is there a more general/clean/better way than hardcoding the whole /usr/local/Cellar/glew/1.12.0/include line to let the compiler know where GLEW is? Should glew.h be located somewhere more general?
Why do I only need this when compiling for android? The mac build doesn't need these flags...
I can't find clear documentation anywhere about this, but in compiling the mac build with GLEW, I didn't need to also install GLU and GLUT (like GLEW's website implied...), and further, neither GLU nor GLUT are available as packages via brew.
I've been looking around for documentation about this, but I feel like I don't know what I don't know. Is there some insight you could give to where I'm going wrong regarding how includes and libraries and stuff are expected to be referenced across platforms?
Welp. Turns out there isn't a straightforward way to include GLEW/GLU/GLUT with NDK? (I have a question mark because I'm still not 100% sure...).
However, I found the solution to my problem, and that was- I didn't need GLEW (or GLU, or GLUT, etc...)!
Like I said, I'm building for OSX and android, so I'm using OpenGL 2.1 and OpenGLES2.
I chose to do this because I was told that OpenGLES2 is simply a subset of OpenGL2, so I didn't expect any issues (so long as I didn't use any func's only in OpenGL 2.1).
I needed GLEW because I wanted to use framebuffers (glGenFramebuffers, etc...), which only exist as an extension in OpenGL 2.1. Once I got that working, I assumed I would need the same extension wrangling for OpenGLES2 on Android- turns out I simply don't! It just kinda works out of the box! (Well, once you get NDK working, and linked with OpenGL, and blah blah blah).
I have code I compiled already, and wonder if I can use the resulting executable, which is in elf format as a library in an APK and how please.
#Gabe Sechan; thanks. I did build a JNI project. I am having some issues importing the code from my other project into JNI. I wonder if you can suggest the best way to import it. I can post my Android.mk file if you like. Basically, it seems that project finds the first file, and an associated header file. That file, in turn uses variables, which are defined in another file. But there is no include statement.
You know? I figured if I can use a JAR file as a library, perhaps I could use an executable also. I need to learn more.
# Chris Straton - Thanks. I did edit my post with a comment to address the toolchain issue. But then, I modified it. Regardless, What I stated was if I use the toolchain that is recommended by my target platform, then I should be able to run it on my phone right?
Further; I re-read your comment about ABI and libc compatibility. The two devices are tegra t132 and Samsung S-N900P. So libc should not be an issue since both devices run Android; right? As far as I know both have an arm chip. Is there anything else I need to look into?
Elf is an executable, not a library. What you want to do is get a .so file and link to it via JNI.
You could possibly run it as a command line program and interact with it via its stdin and stdout, but that would be clunky when you can just use it as an actual library.
I want to use some function calls(commands) designed for linux. I can use them by enter the key words in adb(Android CML).
Here I found some works some people did.
wget (because it isn't included in most Android device )
Iperf
But after reading their methods or suggestions, I can only understand that I need to use Android NDK and write the correct makefile. I have no idea about building others source code (most of them are C/C++) for linux(only need to use 'make' command mentioned in their README file). The official NDK document is for Java environment to call C lib mainly.
Are there some HOWTO, courses or suggestions for this. Thanks!
I have compiled single cpp file program. I try to compile a alternative version iperf
https://github.com/tierney/iperf
It seems to be relative to lib ,some header files, and multiple c files. I failed to compile by enter all c files normally. Is there anything I missed?
yeah you need the NDK, it offers an C/C++ compiler for Android.
In general the steps are all the same:
Setting up the NDK (I wrote a small how-to, but it's for Arch-Linux and the fish-shell, Windows how-to)
Adjusting your make file (instead of gcc compiler use Android NDK compiler, and so on)
Remember that Android uses Bionic C library, so only use functions supported by it
Run make, push the program to your device and make it executable
Of course, this is just an overview how it is done. You should try it and then ask specific questions if you run into troubles.
NDK is mostly intended to extend the Java apps, but you can download NDK and create a standalone toolchain from it (see http://www.kandroid.org/ndk/docs/STANDALONE-TOOLCHAIN.html). Now you have a cross-compilation environment which is very similar to standard Linux dev environment.
In addition, for small executables and for testing only, you can also cross-compile and link statically to the libc. This way you don't have to worry about Bionic which could be a loss of time.