.. highlight:: c

.. _pragma_function_top:

Set Custom Top-Level Function
-------------------------------

**Syntax**


``#pragma LEGUP function top``

**Description**


This pragma specifies the top-level C function that will be compiled to
hardware by LegUp.
All descendant functions called by the top-level C function will be compiled by
LegUp.
By default the top-level is the ``main`` function.

When a custom top-level module is specified, a custom testbench will be needed
for running RTL simulation. Please see :ref:`set_custom_test_bench_module` and
:ref:`set_custom_test_bench_file`.

**Position**

At the beginning of the function definition block.

**Examples**


.. code-block:: c

  int sum(int *a) {
  #pragma LEGUP function top
    ...
  }

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