CMake Examples

(1) lib_and_exe

Compiles a shared library (*.so) and link against an executable

Note

On Linux, *.so are searched a little differently than on Windows. By default, the *.so loader does not search your working directory nor the directory the exe resides.

There are 2 solutions:

1. we set exe's RUNPATH to $ORIGIN, the directory containing the exe.
2. Set LD_LIBRARY_PATH env variable before running the exe. On the other hand, dumping your *.so into system directory is often a no-go due to restricted root access. For more info see RPATH handling

(2) opencl_query_android

Cross-compiles executable that calls OpenCL API and can be adb pushed to mobile device and execute in native environemnt, without using Android Studio

Note

• Need to specify the path of the cross-compiler in the Bash script. Can be downloaded from Android NDK
• Need Android Debug Bridge in your OS-wide path so you can call adb, also downloadble from Android Developers page

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Quick start

CMakeLists.txt syntax

• Only 2 variable types: variable and list of variables
• Set variable by set(MY_VAR MY_NEW_VAR)
• Set list by list(APPEND MY_LIST MY_NEW_ELEMENT)
• ${VAR} are variables, $<COND> are conditionals
• Print debug message with message()

In CMakeLists.txt:
$ set(VAR whatever)
$ message("This is a debug message: the variable VAR is ${VAR}")

After invoking CMake:
This is a debug message: the variable VAR is whatever

• Variables starting with CMAKE_ are pre-defined variables
  • CMAKE_INSTALL_PREFIX: the directory to which your built binaries be exported as packages
  • CMAKE_PREFIX_PATH: the directory CMake search for packages

CMake commands

• cmake -Hsource/dir -Bbuild/dir: generate project from source folder source/dir to build/dir
• cmake --build build/dir --config Release: build binaries from generated project folder build/dir with Release mode