deps/libchdr/deps/zstd-1.5.6/build/cmake/README.md

   1 # Cmake contributions
   2
   3 Contributions to the cmake build configurations are welcome. Please
   4 use case sensitivity that matches modern (i.e. cmake version 2.6 and above)
   5 conventions of using lower-case for commands, and upper-case for
   6 variables.
   7
   8 ## How to build
   9
  10 As cmake doesn't support command like `cmake clean`, it's recommended to perform an "out of source build".
  11 To do this, you can create a new directory and build in it:
  12 ```sh
  13 cd build/cmake
  14 mkdir builddir
  15 cd builddir
  16 cmake ..
  17 make
  18 ```
  19 Then you can clean all cmake caches by simply delete the new directory:
  20 ```sh
  21 rm -rf build/cmake/builddir
  22 ```
  23
  24 And of course, you can directly build in build/cmake:
  25 ```sh
  26 cd build/cmake
  27 cmake
  28 make
  29 ```
  30
  31 To show cmake build options, you can:
  32 ```sh
  33 cd build/cmake/builddir
  34 cmake -LH ..
  35 ```
  36
  37 Bool options can be set to `ON/OFF` with `-D[option]=[ON/OFF]`. You can configure cmake options like this:
  38 ```sh
  39 cd build/cmake/builddir
  40 cmake -DZSTD_BUILD_TESTS=ON -DZSTD_LEGACY_SUPPORT=OFF ..
  41 make
  42 ```
  43
  44 ### how to use it with CMake FetchContent
  45
  46 For all options available, you can see it on <https://github.com/facebook/zstd/blob/dev/build/cmake/lib/CMakeLists.txt>
  47 ```cmake
  48 include(FetchContent)
  49
  50 set(ZSTD_BUILD_STATIC ON)
  51 set(ZSTD_BUILD_SHARED OFF)
  52
  53 FetchContent_Declare(
  54     zstd
  55     URL "https://github.com/facebook/zstd/releases/download/v1.5.5/zstd-1.5.5.tar.gz"
  56     DOWNLOAD_EXTRACT_TIMESTAMP TRUE
  57     SOURCE_SUBDIR build/cmake
  58 )
  59
  60 FetchContent_MakeAvailable(zstd)
  61
  62 target_link_libraries(
  63     ${PROJECT_NAME}
  64     PRIVATE
  65     libzstd_static
  66 )
  67
  68 # On windows and macos this is needed
  69 target_include_directories(
  70     ${PROJECT_NAME}
  71     PRIVATE
  72     ${zstd_SOURCE_DIR}/lib
  73 )
  74 ```
  75
  76 ### referring
  77 [Looking for a 'cmake clean' command to clear up CMake output](https://stackoverflow.com/questions/9680420/looking-for-a-cmake-clean-command-to-clear-up-cmake-output)
  78
  79 ## CMake Style Recommendations
  80
  81 ### Indent all code correctly, i.e. the body of
  82
  83  * if/else/endif
  84  * foreach/endforeach
  85  * while/endwhile
  86  * macro/endmacro
  87  * function/endfunction
  88
  89 Use spaces for indenting, 2, 3 or 4 spaces preferably. Use the same amount of
  90 spaces for indenting as is used in the rest of the file. Do not use tabs.
  91
  92 ### Upper/lower casing
  93
  94 Most important: use consistent upper- or lowercasing within one file !
  95
  96 In general, the all-lowercase style is preferred.
  97
  98 So, this is recommended:
  99
 100 ```
 101 add_executable(foo foo.c)
 102 ```
 103
 104 These forms are discouraged
 105
 106 ```
 107 ADD_EXECUTABLE(bar bar.c)
 108 Add_Executable(hello hello.c)
 109 aDd_ExEcUtAbLe(blub blub.c)
 110 ```
 111
 112 ### End commands
 113 To make the code easier to read, use empty commands for endforeach(), endif(),
 114 endfunction(), endmacro() and endwhile(). Also, use empty else() commands.
 115
 116 For example, do this:
 117
 118 ```
 119 if(FOOVAR)
 120    some_command(...)
 121 else()
 122    another_command(...)
 123 endif()
 124 ```
 125
 126 and not this:
 127
 128 ```
 129 if(BARVAR)
 130    some_other_command(...)
 131 endif(BARVAR)
 132 ```
 133
 134 ### Other resources for best practices
 135
 136 https://cmake.org/cmake/help/latest/manual/cmake-developer.7.html#modules