Cmake Notes
Put this into CMakeLists.txt file. Copied and adapted from various sources on the internet. Lot of time spent on this as documentation doesn’t include examples and people don’t ask that much stuff about cmake.
Build Project
usual mantra. to clean build files (analogue to make clean), just remove Debug directory.
to build Release build, run cmake .. -DRELEASE
mkdir Debug
cd Debug
cmake ..
# cmake .. -DDEBUG
# cmake .. -DRELEASE
Set C or C++ Compiler
# must be before project() command
SET(CMAKE_C_COMPILER /usr/local/Cellar/gcc@6/6.4.0/bin/gcc-6)
SET(CMAKE_CXX_COMPILER /usr/local/Cellar/gcc@6/6.4.0/bin/gcc-6)
or
# must be before project() command
SET(CMAKE_C_COMPILER gcc)
SET(CMAKE_CXX_COMPILER gcc)
note: build scripts should be compiler agnostic and should not rely on a precise path to a compiler, so use this with care or for debug
Set C or C++ Compiler in Different Way
A classic way is also to set C and CXX environment variables which are respected by cmake
export C=gcc
export CXX=g++
Use Headers From Some Library Which Is Not Installed In System
include_directories(AFTER "/Users/pixiedust/Downloads/glibc-2.24")
include_directories(AFTER "/Users/pixiedust/Downloads/glibc-2.24/include")
include_directories(AFTER "/Users/pixiedust/Downloads/glibc-2.24/sysdeps/x86")
include_directories(AFTER "/Users/pixiedust/Downloads/glibc-2.24/sysdeps/generic")
include_directories(AFTER "/Users/pixiedust/Downloads/glibc-2.24/stdio-common")
List Include Path
lists additional paths for inclusion, analogues to -I in gcc, include_directories in cmake. Doesn’t list system dirs though
GET_DIRECTORY_PROPERTY(output INCLUDE_DIRECTORIES)
message("INCLUDE_DIRECTORIES is ${output}")
Show Content of a Variable
message("CMAKE_CXX_FLAGS_DEBUG is ${CMAKE_CXX_FLAGS_DEBUG}")
where CMAKE_CXX_FLAGS_DEBUG is the name of variable
Detect GCC or Clang
if (CMAKE_COMPILER_IS_GNUCXX OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
# do stuff
endif()
Compiler Flags for GCC and Clang
aimed for maximum speed and code quality. copied from various sources from internet
set(CMAKE_CXX_FLAGS_COMMON "-pipe -pedantic -Wall -Wextra -Wshadow -Wno-missing-field-initializers
-Wno-unused-parameter -Wold-style-definition -Wdeclaration-after-statement -Wmissing-declarations
-Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls -Wmissing-noreturn -Wpointer-arith
-Wcast-align -Wwrite-strings -Winline -Wformat-nonliteral -Wformat-security -Wswitch-enum
-Winit-self -Wmissing-include-dirs -Wundef -Waggregate-return -Wnested-externs
-Wunsafe-loop-optimizations -Winvalid-pch -Wcast-qual
")
Additional Flags for Clang
check everything
set(CMAKE_CXX_FLAGS_CLANG "-Wall -Wextra -Wmost -Weverything")
My Compiler Flags for Debug and Production Releases
set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} --std=c99 -g -ggdb -O0 ${CMAKE_CXX_FLAGS_COMMON}")
set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} --std=c99 -Werror -O3 ${CMAKE_CXX_FLAGS_COMMON}")
CMAKE_CXX_FLAGS_DEBUG and CMAKE_CXX_FLAGS_RELEASE are predefined by cmake - Debug and Release builds.
Build .so file (shared object library)
add_library(nss-maria SHARED
"nss/passwd.c"
)
set (nss-maria_VERSION_MAJOR 2)
set (nss-maria_VERSION_MINOR 1)
set (nss-maria_VERSION_PATCH 0)
set(nss-maria_VERSION ${nss-maria_VERSION_MAJOR}.${nss-maria_VERSION_MINOR}.${nss-maria_VERSION_PATCH})
set_target_properties(nss-maria PROPERTIES
VERSION ${nss-maria_VERSION}
SOVERSION ${nss-maria_VERSION_MAJOR}
)
set library + version. copied from KDE5 build configuration. generates these files
lrwxrwxrwx 1 pixiedust staff 17 Dec 27 20:19 libnss-maria.so -> libnss-maria.so.2
lrwxrwxrwx 1 pixiedust staff 21 Dec 27 20:19 libnss-maria.so.2 -> libnss-maria.so.2.1.0
-rwxr-xr-x 1 pixiedust staff 10616 Dec 27 20:19 libnss-maria.so.2.1.0
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