I try to build the Airspy library but I'm having issues, it is not even including Kernel.h headers? I changed Windows SDK in project settings to no effect, and now I am seeing odd errors relating to what seems like perfectly fine syntax:
This is Win8.1 and I tried both in the settings, installing both, but still not compiling. I want to use the library to read audio from radio device but the necessary library isn't compiling (or can I include an Airspy dll and forgo the compile and build step here?)
>> it is not even including Kernel.h headers?
This library is not necessarily used in this header file. It may be used in other header files.
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\Lib , this is the path of kernel32.lib. 1. Confirm the existence of this file. 2. check your Library Directories of VS and confirm that you fill in the path. This is a common solution to the problem of missing files.
I've installed Orwell Dev-C++ 5.x and the PDCurses DevPak. However, when I try to compile the example curses application, the compiler/linker complains that it can't find curses.h. Why?
Before reading any further, keep in mind that Dev-C++ is old software, the use of which is not recommended. Rather use Code:Blocks, Visual Studio or something similar.
The issue being experienced is as a result of the project's configuration being incomplete. Make sure that the "Includes" section (Project Properties) has an entry for the directory containing curses.h ( {installDir}/include) and "Libraries" (also in "Project Properties") has an entry for {installDir}/libs, which contains curses.a.
Ideally, these directories should be set as part of the IDE configuration rather than at the project level. The process of doing so is similar to that described above.
Note that you will have to add the appropriate directories for the curses library and header to a custom makefile (-I for includes and -L for libraries) as part of the project. (Adding it to the auto-generated makefile will not work.) To do this:
Save a copy of the makefile (Makefile.win) made on first compilation (which failed) as Makefile.curses.
Edit the makefile to contain the appropriate directives (-I{installDir}/include after the other includes and -L{installDir}/libs after the other libraries).
In the project's configuration/build options, check 'Use Custom Makefile' and set it to Makefile.curses.
I just started C recently and have been writing some basic C code, but is a bit clueless about how I should go about "installing" libraries like igraph in Visual Studio 2010. I downloaded the igraph "source code for Microsoft Visual Studio" here: http://igraph.sourceforge.net/download.html
(naive) Attempt
There is an "include" folder with all the ".h" files that I copied to the directory that my Visual Studio is set up to look in whenever I use include < something.h > but I get a "unresolved external symbol", which I know means the library isn't set up correctly.
Question
How should I go about "installing" igraph? (and possibly other C libraries)
Look in to the folders of your library, I suppose, you'll find a .lib file there.
Go to your project settings and open the linker settings. Under Input you should find additional dependencies. Add your .lib file(s) there. You also might need to add the folder where this .lib file(s) reside to the library folders (found under VC++-folders).
I have the german version of MSVC here, so your menu entries might be named slightly different, but you will find them ;)
Mark's answer was very helpful, but there were other issues. Following these step resolved it for me. Hopefully this will help someone in the future.
Step 1
The igraph package is a bunch of ".c" and ".h" files that was missing the ".lib" file in Mark's answer. It has to be open and build in Visual Studio. Then, the ".lib" file will appear in the "Debug" folder.
Step 2
Do the steps in Mark's answer.
However, in "VC++ Directories" there is a line call "Include Directories" where you have to store the path to your igraph include directory. This is so that Visual Studio can find the correct files when you write e.g. #include <include/igraph.h>.
Step 3
If you get a "...already defined in MSVCRTD.lib..." error. Then, visit this answer: How to resolve the following linker errors in Visual Studio?
Each of the libraries/subprojects that you are using must be compiled with the same option in "C/C++ -> Code Generation -> Runtime library".
I've installed the msp430-gcc compiler and associated tools to do some open-source msp430 development at home using Eclipse. I'm developing on a slightly older Macbook Pro running OS X Lion and installed the tools using MacPorts. I'm running Eclipse 3.7.2 with the CDT and GCC Cross Compiler Support plug-ins. I have a simple empty main() written that compiles and links just fine.
The ELF parser lets me view the contents of the ELF binary just fine with the exception of one component; when I try to view the contents of the startup code in crt0.S, it gives me a blank file. When I click on the crt0.S component of the ELF, the filename bar at the bottom of the Eclipse window shows "/opt/local/var/macports/build/_Volumes_work_mports_dports_cross_msp430-gcc/msp430-gcc/work/gcc-4.6.3/gcc/config/msp430/crt0.S". This makes sense because of my MacPorts install of msp430-gcc. crt0.S is archived into /opt/local/lib/gcc/msp430/4.6.3/libcrt0.a on my machine.
What I want to be able to do is tell Eclipse to look elsewhere for the source files for the libraries that are automatically linked when I build with the msp430-gcc toolchain. This would presumably include everything in /opt/local/lib/gcc/msp430/4.6.3/. I started by downloading the source for mspgcc-20120406 (the version in my MacPorts install) and applying the gcc patchfile to an empty directory tree. This created the gcc/config/msp430 directory, including the crt0.S and crt0ivtbl.S files.
What I have had no luck accomplishing is telling Eclipse to look in ~/Developer/mspgcc-20120406/gcc-4.6.3/config/msp430/ instead of the path that's in the already-built libcrt0.a. I tried playing around with the Project Preferences->Paths and Symbols->Source Location window, but didn't have much luck. I searched through this website and on Google and the closest thing I came up with was this question but it doesn't "smell" like the right answer.
I would like to avoid solutions that involve moving the library source into my project. I'd rather have a solution that will work for multiple projects.
All help is greatly appreciated! Thanks in advance.
Try and check if the Eclipse linked resource could help you declare that external directory from within your Eclipse project here.
Linked resources are files and folders that are stored in locations in the file system outside of the project's location. These special resources can be used to add files and folders to your project that for some reason must be stored in a certain place outside of your project. For example, a linked folder can be used to store build output separately from your source files.
I find interesting how you can define that linked resource:
Linked resource target paths can be either defined as absolute paths, or relative to a path variable.
Since you can define it relative to (for instance) your Eclipse project location PROJECT_LOC, you can then setup your resource in a way which won't change between two environments.
I'm sure this question has been asked many times, but I can't figure this out. Bear with me.
So when you download a library, you get a bunch of .c and .h files, plus a lot of other stuff. Now say you want to write a program using this library.
I copy all the .h files into my project directory. It just doesn't compile.
Great, so then I get the library as a bunch of .dll's, and i copy the dlls into my project directory. Still doesn't compile.
How does this work?
What do you do, like right after creating the folder for your project? What parts of the library package do you copy/paste into the folder? How do you make it so that it can compile? Go through the steps with me please.
Where to put the .h files?
Where to put the .dll files?
How to compile?
Thanks.
(the library I'm trying to get working is libpng, I'm in windows with MinGW, and i'm looking to compile from command-line like usual.)
(from what i gather, you put the .h files in directory A and the .dll files in directory B and you can use -l and -L compiler options to tell the compiler where to find them, is this correct?)
Here's a brief guide to what happens when you compile and build a basic C project:
The first stage compiles all your source files - this takes the source files you've written and translates them into what are called object files. At this stage the compiler needs to know the declaration of all functions you use in your code, even in external libraries, so you need to use #include to include the header files of whatever libraries you use. This also means that you need to tell the compiler the location of those header files. With GCC you can use the -I command line to feed in directories to be searched for header files.
The next stage is to link all the object files together into one executable. At this stage the linker needs to resolve the calls to external libraries. This means you need the library in object form. Most libraries will give you instructions on how to generate this or might supply it ready built. Under Linux the library file is often a .a or .so file, though it might just be a .o. Again you can feed the location of the library's object file to GCC with the -L option.
Thus your command line would look like this:
gcc myProg.c -I/path/to/libpng/include -L/path/to/libpng/lib -lpng -o myProg.exe
(Note that when using the -l command line GCC automatically adds lib to the start of the library, so -lpng causes libpng.a to be linked in.)
Hope that helps.
Doing it under windows (supposing you user Visual Studio)
After unpacking add the library include directories to your projects' settings (Project -> Properties -> C/C++ -> Additional Include Directories)
Do the same thing for the Libraries Directory (Project -> Properties -> Linker -> Additional Library Directories)
Specify the name of the library in your Linker Input: Project -> Properties -> Linker -> Input -> Additional Dependencies
After this hopefully should compile.
I don't recommend adding the directories above to the Global settings in Visual Studio (Tools -> Options -> Project and Solutions) since it will create and environment where something compiles on your computer and does NOT compile on another one.
Now, the hard way, doing it for a Makefile based build system:
Unpack your stuff
Specify the include directory under the -I g++ flag
Specify the Library directory under the -L g++ flag
Specify the libraries to use like: -llibrary name (for example: -lxml2 for libxml2.so)
Specify the static libraries like: library name.a
at the end you should have a command which is ugly and looks like:
g++ -I/work/my_library/include -L/work/my_library/lib -lmylib my_static.a -o appname_exe MYFILE.CPP
(the line above is not really tested just a general idea)
I recommend go, grab a template makefile from somewhere and add in all your stuff.
You must link against a .lib or something equivalent i.e. add the ".lib" to the libraries read by the linker. At least that's how it works under Linux... haven't done Windows so a long while.
The ".lib" contains symbols to data/functions inside the .dll shared library.
It depends on the library. For examples, some libraries contain precompiled binaries (e.g. dlls) and others you need to compile them yourself. You'd better see the library's documentation.
Basically, to compile you should:
(1) have the library's include (.h) file location in the compiler's include path,
(2) have the library stubs (.lib) location in the linker's library path, and have the linker reference the relevant library file.
In order to run the program you need to have the shared libraries (dlls) where the loader can see them, for example in your system32 directory.
There are two kinds of libraries: static and dynamic (or shared.)
Static libraries come in an object format and you link them directly into your application.
Shared or dynamic libraries reside in a seperate file (.dll or .so) which must be present at the time your application is run. They also come with object files you must link against your application, but in this case they contain nothing more than stubs that find and call the runtime binary (the .dll or the .so).
In either case, you must have some header files containing the signatures (declarations) of the library functions, else your code won't compile.
Some 'libraries' are header-only and you need do nothing more than include them. Some consist of header and source files. In that case you should compile and link the sources against your application just as you would do with a source file you wrote.
When you compile, assuming you have the libs and the headers in the same folder as the sources you are compiling, you need to add to your compile line -L . -I . -lpng. -L tells the linker where to look for the library, -I tells the compiler where to look for the headers and -lpng tells the linker to link with the png library.
[Edit]
Normal projects would have some sort of hierarchy where the headers are in an /include folder and the 3rd party libs are in a /libs folder. In this case, you'd put -I ./include and -L ./libs instead of -I . and -L.
[Edit2] Most projects make use of makefile in order to compile from the command line. You can only compile manually for a small number of files, it gets quite hectic after that
Also,
you may want to look over Dynamic Loading support in various languages and on various
platforms.
This support is very handy in cases when you want to use a library optionally and you don't want your program to fail in case that library is not available.