How do I make Xcode link object files properly?
The file containing "main" and all the dependencies compile properly (and I can easily link them in the command line to generate the executable). However, Xcode seems to refuse to do it, resulting in ld errors of "symbol not found".
This is what my current setup looks like. All the dependencies (Calculator, input, etc) are detected and compile properly. The cpp file contains main but fails to be linked to the .o file (generated by the dependencies), resulting in several ld "symbol not found" errors.
Any ideas?
.o's generated by dependencies do not get linked into the including target. In the example above, "Calculator" needs to generate something, generally a static library (.a), that you would then add to the list of libraries to be linked into the project.
Related
I'm trying to compile a simple Boost Wave example and while Xcode is recognizing the headers, it is giving me a slew of Apple Mach-O Linker(Id) Errors. I have encountered this before and I don't remember how I solved it. Please help!
I have attached a screenshot.
P.S. I have Boost 1.57.0 and it works just fine with any Xcode Project. For whatever reason, though, it isn't in the case when it involves the header boost/wave.hpp like so...
#include <boost/wave.hpp>
Also, I ruled out the body of the code as a culprit. This throws the linker erros:
#include <boost/wave.hpp>
int main() { return 0; }
Other Boost headers like these, do not:
#include <boost/function.hpp>
int main() { return 0; }
I figured it out, but have no idea why this is the case. If anyone would like to add an explanation, that would be splendid. I had to manually add the various dynamic and static libraries referenced in each of the above issues. I attached a new screenshot so others having this issue can see the end result.
Well, the explanation is very simple. In order to be able to build your project, the compiler working under the hood needs to know:
Where to search for the #include <..> within your project's files: this corresponds to the -I directory option for the g++ compiler. In Xcode this corresponds to set the "Header Search Paths" in the Build Settings of you project.
Without specifying the Header Search Paths, you will get errors on the #include lines since Xcode doesn't know where to look for those included files.
Where to search for the library that must be linked to your source code while building the project: this corresponds to the -L directory option for the g++ compiler. In Xcode this corresponds to set the "Library Search Paths" in the Build Settings of you project.
Without specifying the ** Library Search Paths**, you will get errors while trying to build your project since Xcode doesn't know where to look for the linked libraries.
What libraries must be linked to your project files at compilation time: this corresponds to the -l linking option for the g++ compiler.
In Xcode this corresponds to add the .dylib files to the Link Binary With Libraries in the Build Phases settings of your project. Note that you don't need to add manually the libraries to the main folder of your project, the last described step suffice.
See here and here for the directory and linking options of the g++ compiler, respectively.
I just had a fresh new version of Code::Blocks(12.11) and tried to make a glut example project, but the generated code has some linking issues.
The minGW settings are is set to the correct values, since I successfully linked ad compiled a glfw project from *.a files. My problem is the linker just can't handle .lib files for some reason. I always get undefined reference errors, despite of the linking of the correct libraries.
I just don't know what to do/link...
How can I link *.lib files in the new Code::blocks?
IF I cannot, are there any glut binaries in the format of *.a files, or should I build it myself?
Finally I found this link, used this package, and did a clean build(rebuild) of the project, instead of Build. Works like a charm!
I am using dev c++ IDE which used ming gcc(i am not sure of it)
I wanted to use sqlite3 in my win32 c application
I downloaded sqlite3.dll and sqlite3.dev and used dlltool to create a .a file like libsqlite3.a and pasted in the lib folder of dev cpp and added this path in the project options -> parameters
i copied the header file sqlite3.h into the include folder(which i got from another website - http://www.opensource.apple.com/source/SQLite/SQLite-74/derived_source/sqlite3.h)
i executed the program and got the message 'the program can't start because sqlite3.dll is missing in your computer'
so i copied the sqlite3.dll into my working directory and then it worked
BUT
How to make the sqlite.* static while compiling?
I mean i thought by including the libsqlite3.a, the final exe will not be dependent of any external dll's.
So i want to know how to compile in a way that i will not be needing a dll and by doing so it makes my windows program standalone.
do i have a create a .lib file instead of .a file?
EDIT after answers and comments:
Besides, the devpak is working fine... yet i wanted to know how to include files to project or to create .a files so i am trying this way because if some components do not provide devpak then this will be the way we need to compile.. isn't it?
EDIT to show what i have done after the answer by CL and the two comments
This is how i have added the sqlite.c to project list
Here is the compile log
Compiler: Default compiler
Building Makefile:
"C:\Users\jayapalc\Documents\test-sqlite\Makefile.win"
Executing make...
make.exe -f "C:\Users\jayapalc\Documents\test-sqlite\Makefile.win" all
g++.exe -c sqlite3.c -o sqlite3.o -I"lib/gcc/mingw32/3.4.2/include"
-I"include/c++/3.4.2/backward" -I"include/c++/3.4.2/mingw32" -I"include/c++/3.4.2" -I"include"
sqlite3.c: In function `void strftimeFunc(sqlite3_context*, int,
sqlite3_value**)':
sqlite3.c:14727: error: invalid conversion from void*' tochar*'
The files i got in sqlite.org/sqlite-amalgamation-3071502.zip are
shell.c, sqlite3.h, sqlite3.c, sqlite3ext.h and i saw in other discussions that shell.c is not needed...
Besides, people were talking about gcc and g++... .
Apart from updating Dev-C++ itself, try this to compile sqlite.c as a C file:
Go to Project >> Project Options >> Files.
Find the C file we're talking about. Untick "Compile file as C++".
This should inform Dev-C++ that it should invoke gcc.exe, and not g++.exe.
If you don't want to compile sqlite yourself by adding it to your project, you can try passing the -static flag to GCC/G++ to force it to link libsqlite.a statically.
Just include the sqlite3.c file in your project.
You need only this filed, and it must be compiled as C, not C++.
Apparently, Dev-C++ does not allow mixing C and C++ source files in one project.
Instead, you could try to compile sqlite3.c as C and then include the generated .o file into the C++ project (on the Linker page).
I have an Autogen Makefile.am that I'm trying to use to build a test program for a shared library. To build my test binary, I want to continue building the shared library as target but I want the test program to be linked statically. I've spent the last few hours trying to craft my Makefile.am to get it to do this.
I've tried explicitly changing the LDADD line to use the .a version of the library and get a file not found error even though I can see this library is getting built.
I try to add the .libs directory to my link path via LDFLAGS and still it can't find it.
I tried moving my library sources to my test SOURCES list and this won't work because executable object files are built differently than those for static libraries.
I even tried replicating a lib_LIBRARIES entry for the .a version (so there's both a lib_LTLIBRARIES and a lib_LIBRARIES) and replicate all the LDFLAGS, SOURCES, dir and HEADERS for the shared version as part of the static version (replacing la with a of the form _a_SOURCES = _la_SOURCES. Still that doesn't work because now it can't figure out what to build.
My configure.ac file is using the default LT_INIT which should give me both static and dynamic libraries and as I said it is apprently building both even if the libtool can't see the .a file.
Please, anyone know how to do this?
As #Brett Hale mentions in his comment, you should tell Makefile.am that you want the program to be statically linked.
To achieve this you must append -static to your LDFLAGS.
Changing the LDFLAGS for a specific binary is achieved by changing binary_LDFLAGS (where binary is the name of the binary you want to build).
so something like this should do the trick:
binary_LDFLAGS = $(AM_LDFLAGS) -static
I am having a linker error LNK 2001 unresolved external symbol.My point is I do have the respective include directory added under Project Settings->C/C++->General ->Additional Include .I see that this include directory does have the header file which contains the function which is causing the error.
I also add all the lib folders under linker options->general->additional lib dependencies.
What could be going wrong? How can I trace what file is missing?
You need more than just the library path, you need to specify the libraries explicitly. i.e something.lib
(under Linker->Input->Additional Dependencies in VS2005)
Linker errors have nothing to do with include files. You get compiler errors from missing include files/directories. The linker needs the actual definitions aka code to work its magic and create your binary file (exe/dll/static library etc...).
Are you linking to the library of which you are #includeing the headers from?