# CMake Coding Style

###### tags: `Software Management` `DAQ` `DUNE`

### General

* Functions are always to be preferred over macros;
* Named arguments over all but the most basic mandatory unnamed arguments;
* No space between function name and open paren, except for `if`, `else` or `while`;
* Closing paren of a multi-line call on a separate line.

### Indention

Indent all code correctly, i.e. the body of
* if/else/endif
* foreach/endforeach
* while/endwhile
* macro/endmacro
* function/endfunction

Use spaces for indenting, 4 spaces.

### Functions

lower_case name.

Example: `do_something(...)`

### Local variables

lower_case name.

Local variables are used exclusively inside the file that contained them, and their values were simply passed as parameters to CMake functions.

Example: `set(some_variable "...")`

### Global variables

UPPER_CASE name.

Global variables(can also be called “export variables”) are intended for exporting up/down-stream via the environment variable mechanism.

Example: `set(SOME_VARIABLE "...")`

### Control statements

lower_case name without repeating the condition in the closing brackets.

Example:

if(condition)
  ...
else() # not repeat condition
  ...
endif() # not repeat condition

### Operators

UPPER_CASE name.

Example: `if(condition STREQUAL "")`

### Directives and/or extra options

UPPER_CASE name.

Example: `do_something(... USE_THIS)`

## Examples
An real-world example:

function(set_platform system_name)
  if(${system_name} MATCHES "Darwin")
    set(PLATFORM "darwin")
  elseif(${system_name} MATCHES "Linux")
    set(PLATFORM "linux")
  else()
    set(PLATFORM "")
  endif()
endfunction()

cmake_minimum_required(VERSION 3.0)
set_platform(${CMAKE_SYSTEM_NAME})