In CMake my code is
add_library (Hell ${CMAKE_SOURCE_DIR}/libsrc/src/square.cc)
It is creating library as libHell.a and I want to create Hell.a.
This is affected by the PREFIX target property. You can set the prefix to an empty string by using set_target_properties somewhere after the add_library call:
set_target_properties(Hell PROPERTIES PREFIX "")
Related
I'm using the -imacros option for GCC in order to set all preprocessor defines (Options) for a project.
Before imacros I have been using a raw file with the preprocessor defines names and with a regular expression in CMAKE I was creating the list of -D to put in the CMAKE_C_FLAGS.
This works fine but ugly to see in the text editor. So to enhance that, I have changed to -imacros.
CMAKE_C_FLAGS will contain -imacros "path to configuration header"
This works fine, but if I change some configuration item in the configuration header the CMAKE do not recompile the file (don't see changes). In the old version - as you can expect - if some -D was changed all the files will be recompiled.
Any help?
An simple Approach
You can use OBJECT_DEPENDS source file property. But that needs to be set for all source files with something like:
set_source_files_properties(
${sources}
PROPERTIES
OBJECT_DEPENDS "path to configuration header"
)
Alternatives for all Source Files in Project
Officially CMake recommends to put all your definitions in a header file that is included by all your source files. The header could e.g. be generated from a template using configure_file().
But to follow your line of thought with using -imacros compiler flag, here are two alternative approaches for triggering a rebuild of all source files if "path to configuration header" file changes:
You can extend the scope of OBJECT_DEPENDS to all targets and their source files in the current directory with define_property(... INHERITED ...):
If the INHERITED option then the get_property() command will chain up to the next higher scope when the requested property is not set in the scope given to the command. DIRECTORY scope chains to GLOBAL. TARGET, SOURCE, and TEST chain to DIRECTORY.
So in your case this translates to:
define_property(
SOURCE
PROPERTY OBJECT_DEPENDS
INHERITED
BRIEF_DOCS "brief-doc"
FULL_DOCS "full-doc"
)
set_directory_properties(
PROPERTIES
OBJECT_DEPENDS "path to configuration header"
)
If I understand correctly, you anyway have to re-run CMake if your "configuration header" should/would change. Then you can simply add one definition outside your "configuration header" that keeps track of the header with something like:
file(TIMESTAMP "path to configuration header" _timestamp)
add_definitions(-DIMACROS_TIMESTAMP=${_timestamp})
Now every time your header gets a new timestamp, the definitions for all targets are changing and your build system will rebuild all source files.
I'm following a tutorial on CMake and I have problems understanding the necessity of using the 'include_directories' command at one point.
Let me explain the project first:
In my working directory I have:
- a main.cpp function, a CMakeLists.txt(the main one), a configuration file, a 'MathFunction' directory and a 'build' directory
In the MathFunction directory I have:
- a CMakeLists.txt file that will be invoked by the main one
- A file 'mysqrt.cxx' that contains the implementation of a function which will be used in 'main.cpp' application
- A 'MathFunctions.h' header file that contains the prototype of that function
In the CMakeLists from 'MathFunction' directory I'm creating a library using code from 'mysqrt.cxx' like this:
add_library(MathFunctions mysqrt.cxx)
This snippet is a part of my main CMake code:
# add the MathFunctions library?
#
if (USE_MYMATH)
include_directories ("${PROJECT_SOURCE_DIR}/MathFunctions") # WHY DO WE NEED THIS
add_subdirectory (MathFunctions)
set (EXTRA_LIBS ${EXTRA_LIBS} MathFunctions)
endif (USE_MYMATH)
add_executable(Tutorial tutorial.cxx)
target_link_libraries (Tutorial MathFunctions)
Now I do not understand why I need too add that 'include_directories' command in order to use the library? Shouldn't it be enough that the last command 'target_link_libraries' links the already created executable and libraries togheter so there would be no need to also include_directories?
Thank you for reading and I'm sorry if I have not explained it very well but I hope you will understand what I mean :D
Command include_directories sets directories for header files (.h) to be searched. Linking (target_link_libraries) with a library basically specifies only a library file (.so, .dll or other type). As you see, these are different things.
When linking executable with a library target, CMake propagates (more precisely, "consumes") some properties of that library target to the executable. Among these properties there is INTERFACE_INCLUDE_DIRECTORIES property, which adds include directories to the executable.
So, when a library target has INTERFACE_INCLUDE_DIRECTORIES property correctly being set, you don't need to explicitly specify include directories for executable:
MathFunctions/CMakeLists.txt:
add_library(MathFunctions mysqrt.cxx)
# Among other things, this call sets INTERFACE_INCLUDE_DIRECTORIES property.
target_include_directories(MathFunctions PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
CMakeLsits.txt:
add_executable(Tutorial tutorial.cxx)
# This also propagates include directories from the library to executable
target_link_libraries (Tutorial MathFunctions)
Note, that using simple
# This *doesn't* set INTERFACE_INCLUDE_DIRECTORIES property.
include_directories(${CMAKE_CURRENT_SOURCE_DIR})
in MathFunctions/CMakeLists.txt doesn't imply propagating include directories to the linked executable.
Now my CMakeList.txt looking like this.
cmake_minimum_required(VERSION 3.6)
project(RabbitMQClient)
set(CMAKE_CXX_STANDARD 11)
set(SOURCE_FILES main.cpp)
include_directories(src)
include_directories(dependentFile)
add_executable(RabbitMQClient ${SOURCE_FILES})
find_library(SimpleAmqpClient SimpleAmqpClient.2.lib PATHS ./SimpleAmqpClientLib/SimpleAmqpClient.2.lib)
set(IMPORTED_IMPLIB ./SimpleAmqpClientLib)
target_link_libraries(RabbitMQClient PUBLIC SimpleAmqpClient)
when Linking the RabbitMQClient it complains.
cannot find -lSimpleAmqpClient
I want to use the SimpleAmqpClient library in the project,however not quite familiar with cmake not sure the find_library,IMPORTED_IMPLIB,PUBLIC in target_link_libraries was correctly used.Any help would be appreciate.
You have messed up with variables, targets and properties.
Proper usage of IMPORTED libraries for linking would be:
# This command sets *variable* SimpleAmqpClient_LIBRARY
find_library(SimpleAmqpClient_LIBRARY SimpleAmqpClient.2.lib
PATHS ${CMAKE_SOURCE_DIR}/SimpleAmqpClientLib # Specify a *directory*, not a library *file*
)
# Next, create an IMPORTED *target*
add_library(SimpleAmqpClient SHARED IMPORTED)
# And set IMPORTED_LIB *property* for this target
set_target_properties(SimpleAmqpClient PROPERTIES IMPORTED_LIB ${SimpleAmqpClient_LIBRARY})
# Then use library *target* for linking with
target_link_libraries(RabbitMQClient PUBLIC SimpleAmqpClient)
However, there some simplifications which could be done:
Normally, find_library is used when you don't know complete path to the library file. E.g., its directory may be different on different machines, or its prefix/extension may be different on different plaforms.
If you know complete path to the library, just use this path directly (e.g., assign it to the variable).
Normally, property IMPORTED_LOCATION is used for specify library to link with. Property IMPORTED_LIB is specific for Windows .dlls, when linking requires not a library file (.dll), but some other one (.lib).
However, CMake perfectly understands .lib file in IMPORTED_LOCATION property even for Windows .dlls, so your code need not distinguish SHARED Windows libraries from others: just use IMPORTED_LOCATION property in all cases.
Simplified version of the code:
# Create an IMPORTED library *target*
add_library(SimpleAmqpClient IMPORTED)
# Set IMPORTED_LOCATION *property* for this target
set_target_properties(SimpleAmqpClient PROPERTIES
IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/SimpleAmqpClientLib/SimpleAmqpClient.2.lib)
# Then use library *target* for linking with
target_link_libraries(RabbitMQClient PUBLIC SimpleAmqpClient)
I have a project where there's only a handful of logical groupings for generating static libraries. However for convenience I want to have the library's source code to be managed with more granular folders.
Currently the only way I know to do this in CMake without having a library for each folder is to just list files as you would normally in with their relative paths:
add_library(SystemAbstraction STATIC "Some/Path/File.cpp")
However I can see this getting unwieldy as the project grows in size with all the different paths.
I tried to see if I could have a CMakeLists.txt in each folder and just use a variable in the base CMakeLists.txt when adding library dependencies. But it seems that add_subdirectory doesn't also import variables?
For expanding the scope of a variable inside a subdirectory, use the PARENT_SCOPE option of set. For example, you can test that if you have
# CMakeLists.txt
set(SRCS main.c)
add_subdirectory(foo)
message(${SRCS})
in the root directory and
# foo/CMakeLists.txt
set(SRCS ${SRCS} foo.c PARENT_SCOPE)
in a subdirectory then it will print main.c foo.c, i.e., the variable is correctly imported into the base CMakeLists.txt.
An option would be to use the object library feature of CMake. You still can but doesn't need to organise your CMake script into subdirectories:
add_library(lib1 OBJECT <srcs>)
add_library(lib2 OBJECT <srcs>)
...
add_library(mainlib $<TARGET_OBJECTS:lib1> $<TARGET_OBJECTS:lib2>)
You can set different compile flags for each object library:
target_include_directories(lib1 PRIVATE incl-dir-for-lib1)
target_compile_definitions(lib2 PRIVATE def-for-lib2)
You still need to set link libraries on your main library:
target_link_libraries(mainlib PRIVATE deps-of-lib1 deps-of-lib2)
Related documentation: Object Libraries
I was wondering if there is an Xcode or GCC preprocessor symbol for the target name of the application.
For example if I'm building an application called "MonkeyChicken", is there a preprocessor symbol such that
printf( __TARGET_NAME__ )
outputs:
MonkeyChicken
I don't believe there is any built-in (gcc has no idea what you're building when you compile a file), but you can always create one using GCC_PREPROCESSOR_DEFINITIONS in an xcconfig file (you are using xcconfig, right?) Something like this should work as you indicate above:
GCC_PREPROCESSOR_DEFINITIONS = __TARGET_NAME__=\"$(PRODUCT_NAME)\"