A h-- file extension is related to the Sphinx C-- and used for its header files.
H-- file extension - Sphinx C-- header
What is h-- file? How to open h-- files?
File type specification:
C-- is a medium- to low-level language for 80x86 machines. It is small, efficient, and ideal for writing utilities, memory-resident programs, and just about anything else where assembly language might be used. It gives the power of assembly with the readability of a high-level language.
This h-- file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.