summaryrefslogtreecommitdiff
path: root/Help/command/function.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Help/command/function.rst')
-rw-r--r--Help/command/function.rst36
1 files changed, 36 insertions, 0 deletions
diff --git a/Help/command/function.rst b/Help/command/function.rst
new file mode 100644
index 000000000..7ffdfee65
--- /dev/null
+++ b/Help/command/function.rst
@@ -0,0 +1,36 @@
+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.
+
+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.