vhdl_input_version Synthesis Directive

A VHDL synthesis directive that specifies the VHDL language version for the design units in a VHDL Design File (.vhd) Definition. This directive overrides the default HDL version and any HDL version specified in the File Properties dialog box.

-- synthesis VHDL_INPUT_VERSION <language version>

To use the VHDL_INPUT_VERSION directive, embed it in a VHDL comment at the point where you want to start using that language version. This directive takes a single string argument, the <language version> of the VHDL language you wish to use, which can be either VHDL_1987, VHDL_1993, or VHDL_2008.

Note: You cannot change VHDL language versions in the middle of a VHDL design unit.

When the Intel® Quartus® Prime software reads a VHDL_INPUT_VERSION directive, it changes the current language version as specified until the end of the file, or until it reaches the next VHDL_INPUT_VERSION directive.