.. highlight:: c

.. _pragma_memory_impl_contention_free:

Contention-Free Memory Access 
-------------------------------

**Syntax**

``#pragma LEGUP memory impl variable(<arg_name>) contention_free(true|false)``

**Description**

The pragma is to be used for variables accessed by parallel functions (``legup::thread``)
so that LegUp does not create arbiters for the specified variable.
The specified variable can still be accessed by multiple concurrently running functions, but without contention.
It will be the users’ responsibility to ensure at most one function may access the shared
variable in a clock cycle. If not specified, by default,
LegUp creates arbiters for variables that are accessed by parallel functions.


**Parameters**

+---------------------+-------------------+----------+-----------+-------------------------------------+
|      Parameter      |       Value       | Optional |  Default  |             Description             |
+=====================+===================+==========+===========+=====================================+
| ``variable``        | String            | No       |           | Variable name                       |
+---------------------+-------------------+----------+-----------+-------------------------------------+
| ``contention_free`` | ``true -  false`` | Yes      | ``false`` | ``true`` for contention-free access |
+---------------------+-------------------+----------+-----------+-------------------------------------+

**Position**

Before the global / local variable declaration.


**Examples**

.. code-block:: c

  #pragma LEGUP memory impl variable(b) contention_free(true)
  int b[100];

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