AHDL Function Prototype (port name and order also apply to Verilog HDL)
The following AHDL function prototype is located in the AHDL Include File (.inc) Definitionaltsource_probe.inc in the <Intel® Quartus® Prime installation directory>\libraries\megafunctions directory.
FUNCTION altsource_probe( probe[probe_width-1..0], source[source_width-1..0], source_clk, source_ena ) WITH( enable_metastability, instance_id, lpm_hint, lpm_type, probe_width, sld_auto_instance_index, sld_instance_index, source_initial_value, source_width ) RETURNS( source[source_width-1..0] );