I'm building a project that uses cmake.
The project uses three shared libraries .so files.
In the CMakeLists.txt file I've added the these lines which link the shared libraries to the executable.
project (lwm2mclient)
LINK_DIRECTORIES(/home/mraa-master-built/build/src)
LINK_DIRECTORIES(/home/libi2capi)
LINK_DIRECTORIES(/home/libtca6424a)
target_link_libraries (lwm2mclient libmraa.so m libi2capi.so libtca6424a.so)
However, one of the shared libraries libtca6424a.sodepends on libi2capi.so i.e. it uses methods that are defined in it.
So when I'm building the cmake project I get an error like this saying that the .so file cannot find the method which is defined in the other .so file libtca6424a.so.
Could somebody suggest a solution?
/../../lib/libtca6424a.so: undefined reference to `i2c_write_byte_data'
Please try
target_link_libraries (-Wl,--start-group lwm2mclient libmraa.so m libi2capi.so libtca6424a.so -Wl,--end-group)
or change the order of the libraries
Related
I have a c language program that has the following structure:
src/main/c/main.c
src/main/headers/main.h
src/module_1/c/module_1.h
src/module_1/headers/module_1.h
...
src/modulen/c/module_n.c
src/module/headers/module_n.h
In the gradle script I have defined:
components {
module_1(NativeLibrarySpec)
...
module_n(NativeLibrarySpec)
main(NativeExecutableSpec){
sources{
c.lib library: "module_1", linkage: "static"
...
c.lib library: "module_n", linkage: "static"
}
The reason of using this structure is to facilitate creating unit tests for each module separately.
The problem comes with the inclusion of the .h files from the modules in the main or in other modules (there are some dependencies between them). I haven't found a way to make the headers of a module available to other modules. I would actually like to make them all "global" to the project (that is, automatically added to the source set for any module).
Thanks in advance
I do not know gradle but may give you some general advise.
I haven't found a way to make the headers of a module available to other modules.
You could make a central directory (repository) for all .h files of your project, for example src/include. The header files of each module can be placed there (in the version of the curent baseline).
I would actually like to make them all "global" to the project (that is, automatically added to the source set for any module).
The above repository can support that. However, including a header in a source file is a manual task. It is also wise not to include all headers into a source file; it may only need a few.
I have a static library for a Vector implementation in C.
I am now making a new library that is going to rely on the Vector in order to function property. This new library is called String. Both are static libraries created in Visual Studio with their own .c and .h files.
I do the following just like I would when referencing any other static library
Create new static library. Create .c and .h files in it.
project -> properties -> C/C++ -> Additional include directories and set as the folder that contains the .c and .h files for my Vector
File -> Add -> Existing Project and set the .vcxproj file of the Vector project.
In my solution explorer, I went under my String solution and right clicked References and then check-marked the Vector box that shows up.
At this point, my String is now correctly able to see Vector.
The problem
When I open a new project, repeat those same steps except with String as the target library, I get the following error:
Severity Code Description Project File Line Suppression State
Error MSB8006 The Platform for project 'C-DataStructuresLib.vcxproj' is invalid. Platform='HPD'. This error may also appear if some other project is trying to follow a project-to-project reference to this project, this project has been unloaded or is not included in the solution, and the referencing project does not build using the same or an equivalent Platform. CStringLib C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V140\Microsoft.Cpp.InvalidPlatform.Targets 21
The line:
This error may also appear if some other project is trying to follow a project-to-project reference to this project, this project has been unloaded or is not included in the solution, and the referencing project does not build using the same or an equivalent Platform
Is correct because that's exactly what I'm trying to do. How can this be fixed?
Are you trying to compile as 64-bit project?
Check in the property page the section: Linker -> Advanced -> Target Machine
I am using the LPCXpresso IDE to program my microcontroller to use the libjpeg library for a particular application. However, I cannot seem to get the LPCXpresso IDE to recognize libjpeg. The way I see it, there are two options:
1) Take the jpeglib.a file, include it as an external library, and then attempt to import jpeglib.h. I have tried this, at the IDE still does not recognize jpeglib.h.
2) Create a new static library from the libjpeg source code. Is this my only option? It seems a bit excessive.
Any tips regarding adding/linking external libraries in LPCXpresso would be greatly appreciated. Thanks!
You can easily add a library to Eclipse/LPCXpresso by creating a new project (not a C project or a LPCXpresso project but a 'normal' project) by clicking File->New->Project. Name is as you wish, let's say 'JPEG'. Add your library file to it under the folder 'lib' (you have to create the folder first). Call the library file 'libJPEG.a'. Also include the header file under the folder 'inc'. It is not mandatory to create these folders by the way, but it makes it all more organised.
The edit the properties of the project that's needs to include the header and library. Right click the project and choose properties. Go to C/C++ Build->Settings->MCU C compiler->Includes and add the include path of the inc folder of the library project. The go to C/C++ Build->Settings->MCU Linker->Libraries and add the library file WITHOUT the lib in front of the file name, hence just JPEG. Also add the library search path below (point to the lib folder).
That's all!
I'm trying to use the SkypeKit SDK to create an Objective-C++ project using Xcode 4. I have two compiled libraries from SkypeKit, libskypekit_cyassl_lib.a and libskypekit_cppwrapper_2_lib.a, which I need to be able to use so as to access the Skype API.
I've added in both .a files under 'Linked Frameworks and Libraries' and added -all_load -ObjC -lstdc++ to the 'Other Linker Flags', and that builds okay, but as soon as I try to use any of the methods in those libraries, building fails.
Any help would be greatly appreciated, thank you!
You can call C++ code from Objective-C++, which means that your files should have the .mm extension instead of .m
I assume that this could be the issue, but since you did not specify the errors you get it is just a guess. Specifically, if you call C++ code from a .m file you get compilation errors.
Another possible cause is forgetting to import the header files of the library. For the import to be successful, you also have to add the directory where the headers are to your project "header search path".
If this does not help, please post the error message.
Ok, so here's my question:
I have a working DUB project which produces an application. I decided I also wanted a "library" configuration in my dub.json file:
"configurations": [
{
"name": "application",
"targetType": "executable"
},
{
"name": "library",
"targetType": "library",
}
],
So, now when I build the project using dub build --config=library, it produces a libXXXX.a file in the same directory.
So far, so good.
I tried using this library (actually a tiny test-function marked as extern "C" from a test C app).
So, I compile my C app using gcc -c ctest.c and then link them all together like dmd libMYLIBRARY.a ctest.o.
Now, here is the problem:
In this last step, the linker complains that many symbols are missing - all coming from external dependencies (2 object files and several .a libraries) that would normally be linked when building the project as an application.
So, the question is... how do I solve this?
I mean... Should I just link my test C app against ALL of the original dependencies (this would not make the library very portable admittedly), or is there any way around it, so that anybody could use my library, only by linking against my libXXXXX.a file?
Should I just link my test C app against ALL of the original dependencies (this would not make the library very portable admittedly),
This is the "technically correct" answer. The reason for that is because, otherwise, if the C app wanted to use another D library which had among its dependencies some package that's also a dependency in your library, and if it were linked in the same way (including all of its dependencies in its static library file), this dependency would then occur twice in the linker inputs. Even if you told the linker to discard one copy, there can be problems due to the dependency being of separate incompatible versions, etc. (Note that there is an ongoing D SAOC project to handle this.)
If you were to assume that the only D library the C program will use is your Dub package, then you could conceivably create a static library which includes all dependencies, though it would probably need to include the D standard library and runtime as well.