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Diffstat (limited to 'Help/command/function.rst')
-rw-r--r-- | Help/command/function.rst | 88 |
1 files changed, 61 insertions, 27 deletions
diff --git a/Help/command/function.rst b/Help/command/function.rst index 7ffdfee..53ba754 100644 --- a/Help/command/function.rst +++ b/Help/command/function.rst @@ -1,36 +1,70 @@ function -------- -Start recording a function for later invocation as a command:: - - function(<name> [arg1 [arg2 [arg3 ...]]]) - COMMAND1(ARGS ...) - COMMAND2(ARGS ...) - ... - endfunction(<name>) - -Define a function named ``<name>`` that takes arguments named ``arg1``, -``arg2``, ``arg3``, (...). -Commands listed after function, but before the matching -:command:`endfunction()`, are not invoked until the function is invoked. -When it is invoked, the commands recorded in the function are first -modified by replacing formal parameters (``${arg1}``) with the arguments -passed, and then invoked as normal commands. -In addition to referencing the formal parameters you can reference the -``ARGC`` variable which will be set to the number of arguments passed -into the function as well as ``ARGV0``, ``ARGV1``, ``ARGV2``, ... which -will have the actual values of the arguments passed in. -This facilitates creating functions with optional arguments. -Additionally ``ARGV`` holds the list of all arguments given to the -function and ``ARGN`` holds the list of arguments past the last expected -argument. -Referencing to ``ARGV#`` arguments beyond ``ARGC`` have undefined -behavior. Checking that ``ARGC`` is greater than ``#`` is the only way -to ensure that ``ARGV#`` was passed to the function as an extra -argument. +Start recording a function for later invocation as a command. + +.. code-block:: cmake + + function(<name> [<arg1> ...]) + <commands> + endfunction() + +Defines a function named ``<name>`` that takes arguments named +``<arg1>``, ... The ``<commands>`` in the function definition +are recorded; they are not executed until the function is invoked. + +Per legacy, the :command:`endfunction` command admits an optional +``<name>`` argument. If used, it must be a verbatim repeat of the +argument of the opening ``function`` command. A function opens a new scope: see :command:`set(var PARENT_SCOPE)` for details. See the :command:`cmake_policy()` command documentation for the behavior of policies inside functions. + +See the :command:`macro()` command documentation for differences +between CMake functions and macros. + +Invocation +^^^^^^^^^^ + +The function invocation is case-insensitive. A function defined as + +.. code-block:: cmake + + function(foo) + <commands> + endfunction() + +can be invoked through any of + +.. code-block:: cmake + + foo() + Foo() + FOO() + +and so on. However, it is strongly recommended to stay with the +case chosen in the function definition. Typically functions use +all-lowercase names. + +Arguments +^^^^^^^^^ + +When the function is invoked, the recorded ``<commands>`` are first +modified by replacing formal parameters (``${arg1}``, ...) with the +arguments passed, and then invoked as normal commands. + +In addition to referencing the formal parameters you can reference the +``ARGC`` variable which will be set to the number of arguments passed +into the function as well as ``ARGV0``, ``ARGV1``, ``ARGV2``, ... which +will have the actual values of the arguments passed in. This facilitates +creating functions with optional arguments. + +Furthermore, ``ARGV`` holds the list of all arguments given to the +function and ``ARGN`` holds the list of arguments past the last expected +argument. Referencing to ``ARGV#`` arguments beyond ``ARGC`` have +undefined behavior. Checking that ``ARGC`` is greater than ``#`` is +the only way to ensure that ``ARGV#`` was passed to the function as an +extra argument. |