Currently I am working with the Android NDK and JNI. I am trying to build a C++ code with NDK.
But I got the following errors:
E:/Android/Tranining_workspace/BackUpMigrant/jni/ReadBackupArc5/ReadBackupArc5.cpp:10:19: error: fstream: No such file or directory
E:/Android/Tranining_workspace/BackUpMigrant/jni/ReadBackupArc5/ReadBackupArc5.cpp:20: error: 'ifstream' does not name a type
E:/Android/Tranining_workspace/BackUpMigrant/jni/ReadBackupArc5/ReadBackupArc5.cpp:21: error: 'ofstream' does not name a type
E:/Android/Tranining_workspace/BackUpMigrant/jni/ReadBackupArc5/ReadBackupArc5.cpp:22: error: 'ofstream' does not name a type
E:/Android/Tranining_workspace/BackUpMigrant/jni/ReadBackupArc5/ReadBackupArc5.cpp:34: error: 'string' was not declared in this scope
Can anyone please help me out?
I just encountered the same problem. Seems the STL is not automatically included in NDK projects by default. That also means iostream, fstream, string etc can't be used straight away. To enable them, you'll need to modify your Application.mk file. If you don't have one (it's in the <project>/jni directory), then just create a new, blank one. Add the line:
APP_STL := stlport_static
Also, also remember to include using namespace std; or equivalent, along with the usual #include <iostream> etc.
Did you remember your:
#include <iostream>
using namespace std;
definitions at the top of the file?
("using namespace std" isn't always a good idea, but that's a separate issue.)
Related
Im trying to build an Ubuntu Touch tree, based on an Aosp tree I already correctly built.
It fails with this error
CAPEWrapper.cpp:16: error: undefined reference to '__xlog_buf_printf'
this is the header that file includes
#include "CAPEWrapper.h"
which on cascade includes
#include <cutils/xlog.h>
which in turn defines
#if defined(__cplusplus)
extern "C" {
#endif
int __xlog_buf_printf(int bufid, const struct xlog_record *rec, ...);
#if defined(__cplusplus)
}
#endif
I suspect that my g++ doesn't set __cplusplus macro. Could it be a realistic scenario with this kind of error? If this could be the problem, should I need to specify a standard implementation with "stdc=something" to solve it?
Any other idea is welcome.
Make sure that your project is linking libcutils, and that it's linking it in the correct order (i.e. that -lcutils appears in the linker command line after any module that depends on it).
In the end, I found that the modules was listed inside a macro called LOCAL_WHOLE_STATIC_LIBRARIES, that in Android environment passes its content to the --whole-archive flag of GCC linker.
I have an Android application that use JNI. In JNI I used C++ STL library to output some data into a text file.
This is the snippet code.
#include <iostream>
#include <fstream>
float mydata[4] = {0.0f};
ofstream file;
file.open("Data.txt", ios::app);
// For example
file<<mydata[1];
file.close();
when I ran ndk-build, I did not face any errors and the program seems run properly. But I did not found any text file in my Application directory.
does anybody know what could be the issue? Please help.
Thanks
Your code works, but you apparently try to access a path which is forbidden.
Firstly, be sure that your Android application asks for storage permissions.
Secondly, try to replace "Data" by an absolute path you know you have access to (e.g. "/sdcard/Pictures/Data.txt").
Also, as a better practice, you should test if the file has been opened before writing to it.
I'm creating a native android project using eclipse. I'm using opengl es 1.1.
I get this error when using a function from the glext.h file
Function 'glDrawTexfOES' could not be resolved
I'm using a function from gl.h right before i call the glDrawTexfOES. I'm able to use macros defined in the glext.h such as GL_TEXTURE_CROP_RECT_OES, so i know the file is included all right.
looking at the glext.h file, i found the function declaration i want, which is in an #ifdef block (#ifdef GL_GLEXT_PROTOTYPES). I defined GL_GLEXT_PROTOTYPES immediately before including glext.h, and i still have the same problem. I went into glext.h and edited it, first by commenting the ifdef and endif lines surrounding the functions i want. i still got the same error as above. then i copied the function declaration and pasted it at the top of the glext.h file, and my project still says it can't resolve that function.
I know glext.h is deprecated, but i should still be able to use it
I had this same issue, but then put this in my Android.mk file:
LOCAL_CFLAGS += -D GL_GLEXT_PROTOTYPES
http://grokbase.com/t/gg/android-ndk/11cxrckjmp/ndkr7-cant-see-gldrawtexioes
I am trying to get cocos2d-android (cocos2d-2.0-rc2-x-2.0.1) "Helloworld" sample to run under windows. I am using latest version of cygwin along side with android ndk r6, android sdk API 8. And I tried the manual here
after a lot of challenges I am down to this problem which I think is in linking the classes at compile time. when I try to run the *build_native.sh* script I get an error stating that in CCGL.h, PFNGLDELETEVERTEXARRAYSOESPROC which is defined as extern, does not name a type.
//declare here while define in CCEGLView_android.cpp
extern PFNGLGENVERTEXARRAYSOESPROC glGenVertexArraysOESEXT;
extern PFNGLBINDVERTEXARRAYOESPROC glBindVertexArrayOESEXT;
extern PFNGLDELETEVERTEXARRAYSOESPROC glDeleteVertexArraysOESEXT;
'PFNGLDELETEVERTEXARRAYSOESPROC' is declared in CCEGLView.h.
#if CC_TEXTURE_ATLAS_USE_VAO
#include <EGL/egl.h>
PFNGLGENVERTEXARRAYSOESPROC glGenVertexArraysOESEXT = 0;
PFNGLBINDVERTEXARRAYOESPROC glBindVertexArrayOESEXT = 0;
PFNGLDELETEVERTEXARRAYSOESPROC glDeleteVertexArraysOESEXT = 0;
#endif
I tried to add the header address to android.mk under jni directory, to LOCAL_C_INCLUDES, as suggested here,but there were no rules to make them. so can anybody help me with how to compile/link this, it would be much appreciated.
I had this problem, and using a higher version of NDK worked. Try to get the most recent version, reset the environment variables, and run build_native.sh again.
http://developer.android.com/tools/sdk/ndk/index.html
I am trying to build a C++ code using NDK in android. I have a method which has a parameter vector < vector <float> > coordinates
Everything builds fine until I write this line inside my method
vector<float> firstPoint = coordinates.at(0);
I start getting this error
D:/eclipseworkspace/myLibProject/obj/local/armeabi/libmyLibProject.a(FileName.o): In function `std::priv::_Vector_base<std::vector<float, std::allocator<float> >, std::allocator<std::vector<float, std::allocator<float> > > >::_M_throw_out_of_range() const':
D:/androidndk/sources/cxx-stl/stlport/stlport/stl/_vector.c:45: undefined reference to `std::__stl_throw_out_of_range(char const*)'
collect2: ld returned 1 exit status
make: *** [/cygdrive/d/eclipseworkspace/myLibProject/obj/local/armeabi/libOutputName.so] Error 1
I have no clue why this is happening and Google is not helping either.
Thanks.
I think you are using two different implementation of the standard library in the same project.
It looks like you are compiling your files with (the headers of) an stlport implementation of the standard library in D:/android..., and you link against your local library.
You have to configure the linker in your ide (or Makefile) to use also the lib file of the same implementation (somewhere in D:/android... I guess).
This is a linking error. You need to add APP_STL := stlport_static to your Apllication.mk file. Also make sure that you use -fno-exceptions flag, since STLport is not compatible with C++ exceptions and RTTI.
You can get more info in APPLICATION-MK.HTML which is availavle in the docs folder of the NDK. CPLUSPLUS-SUPPORT.HTML is also worth to read.
this looks like a linker error. You probably forgot to add STL library reference to your build. Or it can't be found
Did you do this ?
#include <stdexcept>
#include <vector>
using namespace std;
When I changed
vector<float> firstPoint = coordinates.at(0);
to
vector<float> firstPoint = coordinates[0];
it started compiling..... :s y?