I have a library file with .lib extension. I want to use this file in my project which uses GCC compiler to build.
Is it possible to use the .lib file?? I tried but I got this error:
"File Format not recognized."
Related
I am tring to build linux kernel using clang/llvm. I am trying to save the .bc file while generating the .o file . I find LLVM have the API "writebitcodetofile" whcich can save the bc code to certain file, but I am not sure how to use it.
There is a number of flags that can do that for you:
-flto enables Link-time optimization, which uses LLVM bitcode. In this case (almost) all the .o files will in fact contain the bitcode.
-save-temps tells clang to put the results of each intermediate phase into a separate file. Simple clang -save-temps main.c may output main.o, main.bc, main.i, main.s, or object file, bitcode file, preprocessed file, and assembly file, respectively.
-fembed-bitcode tells clang to include the bitcode representation of a file into the resulting object file. You can learn more about this here: https://jonasdevlieghere.com/libebc-ebcutil/
Note, however, that you won't get bitcode for assembly files.
My library has minimal, straightforward CMake code with the pertinent lines
add_library(MyLib <sources>)
install(
TARGETS MyLib
LIBRARY DESTINATION ${destination}/lib
RUNTIME DESTINATION ${destination}/lib
COMPONENT Libraries)
install(
FILES mylib.h
DESTINATION ${destination}/include
COMPONENT Headers)
When executed under Windows, the system generates mylib.dll in ...\build\Release, and mylib.lib and mylib.exp (what's that?) in ...\build\lib\Release. It only installs mylib.dll.
My application has minimal, straightforward CMake code to search for my library:
find_path(MyLib_INCLUDE_DIR mylib.h)
find_library(MyLib_LIBRARIES NAMES MyLib)
include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(MyLib DEFAULT_MSG MyLib_LIBRARIES MyLib_INCLUDE_DIR)
Which works under Linux, but under Windows results in
-- Could NOT find MyLib (missing: MyLib_LIBRARIES)
From experimentation I know that this error occurs whenever there is only a .DLL file, and no associated .LIB import library.
Shall I correct MyLib to install mylib.lib? How?
Or is it possible to modify my application so that it is satisfied with mylib.dll only? How?
Research done so far
This is not about static vs dynamic linking (DLL and LIB files - what and why?, cmake link against dll/lib): I want dynamic linking; if a .LIB file is required, it has nothing to do with static linking.
This link cmake : shared library : how to get the .lib name instead of .dll name? may be pertinent, but is not explicit enough. Two other questions CMake generated VS project expecting lib instead of dll, Linking dll/lib to a cmake project seem related, but have no answer.
Command install classifies .lib file for a shared library as ARCHIVE. This is explicitly stated in the documentation:
For DLL platforms (all Windows-based systems including Cygwin), the DLL import library is treated as an ARCHIVE target.
So you need to add ARCHIVE clause to install() for install .lib file as well:
install(
TARGETS MyLib
ARCHIVE DESTINATION ${destination}/lib
LIBRARY DESTINATION ${destination}/lib
RUNTIME DESTINATION ${destination}/bin
COMPONENT Libraries)
Not also, that RUNTIME DESTINATION is usually specified as bin, the same as destination for executables. This helps the executables on Windows to locate the shared libraries (.dll).
I had some code that wasn't working until I added extern "C" before the name of a function, even though I was compiling using gcc. The file's name did, however, end in ".cpp".
Is it possible for gcc to name mangle? Did it intelligently pick up the file extension ".cpp"?
The gcc compiler driver looks at the file extension. If it is .cpp (or .cc, .C and a few more), the file is compiled as a C++ file:
Compiling C++ Programs
I have a CMake file which does this:
find_package(Boost COMPONENTS system filesystem)
add_library(MyModule MODULE main.cpp)
target_include_directories(MyModule PUBLIC ${Boost_INCLUDE_DIRS})
target_link_libraries(MyModule Boost::system Boost::filesystem)
I'm using VS 2017 as my generator. When I generate the project file with cmake, it finds boost_system-vc141-mt-1_63.lib and I can see that it is in the linking rules of the vcxproj. However, when I try to compile I get this error:
LINK : fatal error LNK1104: cannot open file 'libboost_system-vc140-mt-1_63.lib
Note the different generators (vc140 vs vc141). I know my compiler has output the right values because I built boost from source, so I tried to just rename vc141 to vc140, but the error stayed the same. I also confirmed that vc140 is not referenced in the project file.
What's going on? How can I force boost to link to the correct version?
When building with Visual Studio, boost has some pragma statements which do the linking for you. This is called "Auto-linking" and it over-rides any command-line arguments you may be passing to the linker.
The solution is to define BOOST_ALL_NO_LIB. This can be done in two ways:
In source code before including boost headers as #define BOOST_ALL_NO_LIB.
It could be added to your cmake file as: add_definitions("-DBOOST_ALL_NO_LIB").
As of CMake 3.5: Use the disable_autolinking imported target:
target_link_libraries(MyModule Boost::system Boost::filesystem Boost::disable_autolinking)
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).