fish-shell/sphinx_doc_src/cmds/block.rst

.. _cmd-block:

block - temporarily block delivery of events
============================================

Synopsis
--------

block [OPTIONS...]


Description
-----------

``block`` prevents events triggered by ``fish`` or the :ref:`emit <cmd-emit>` command from being delivered and acted upon while the block is in place.

In functions, ``block`` can be useful while performing work that should not be interrupted by the shell.

The block can be removed. Any events which triggered while the block was in place will then be delivered.

Event blocks should not be confused with code blocks, which are created with ``begin``, ``if``, ``while`` or ``for``

The following parameters are available:

- ``-l`` or ``--local`` Release the block automatically at the end of the current innermost code block scope

- ``-g`` or ``--global`` Never automatically release the lock

- ``-e`` or ``--erase`` Release global block


Example
-------



::

    # Create a function that listens for events
    function --on-event foo foo; echo 'foo fired'; end
    
    # Block the delivery of events
    block -g
    
    emit foo
    # No output will be produced
    
    block -e
    # 'foo fired' will now be printed



Notes
-----

Note that events are only received from the current fish process as there is no way to send events from one fish process to another.