block

.. versionadded:: 3.25

Evaluate a group of commands with a dedicated variable and/or policy scope.

.. code-block:: cmake

block([SCOPE_FOR [POLICIES] [VARIABLES]] [PROPAGATE <var-name>...]) <commands> endblock()

All commands between block() and the matching :command:endblock are recorded without being invoked. Once the :command:endblock is evaluated, the recorded list of commands is invoked inside the requested scopes, then the scopes created by the block() command are removed.

SCOPE_FOR Specify which scopes must be created.

POLICIES Create a new policy scope. This is equivalent to :command:cmake_policy(PUSH) with an automatic :command:cmake_policy(POP) when leaving the block scope.

VARIABLES Create a new variable scope.

If SCOPE_FOR is not specified, this is equivalent to:

.. code-block:: cmake

block(SCOPE_FOR VARIABLES POLICIES)

PROPAGATE When a variable scope is created by the :command:block command, this option sets or unsets the specified variables in the parent scope. This is equivalent to :command:set(PARENT_SCOPE) or :command:unset(PARENT_SCOPE) commands.

.. code-block:: cmake

set(var1 "INIT1")
set(var2 "INIT2")
set(var3 "INIT3")

block(PROPAGATE var1 var2)
  set(var1 "VALUE1")
  unset(var2)
  set(var3 "VALUE3")
endblock()

# Now var1 holds VALUE1, var2 is unset, and var3 holds the initial value INIT3

This option is only allowed when a variable scope is created. An error will be raised in the other cases.

When the block() is inside a :command:foreach or :command:while command, the :command:break and :command:continue commands can be used inside the block.

.. code-block:: cmake

while(TRUE) block() ... # the break() command will terminate the while() command break() endblock() endwhile()