.CH File Extension
File TypeClipper Header File
What is a CH file?
A CH file is a header file used by programs written in the Clipper programming language. It contains pre-processor directives and external declarations that are then included in Clipper .PRG files, by referencing the CH file using the #include directive. CH files are now most often used by programs written in the Harbour programming language.
Clipper is a programming language and compiler that uses a variant of the xBase programming language to allow developers to write and distribute MS-DOS programs. Created by the Nantucket Corporation in 1985, Clipper was renamed CA-Clipper when Nantucket was acquired by Computer Associates in 1992.
When creating Clipper programs, developers could create Clipper header files that allowed them to define fixed variables and perform other pre-processor directives outside of Clipper program files (PRGs). This allowed developers to quickly and easily include the same pre-processor directives in many different program files, reducing the amount of code clean-up needed if a pre-processor directive needed to be changed. (If the directive was manually included in many PRG files, developers would have to manually update each PRG's instance of the directive, rather than updating just the single CH file.)
As the Windows operating system replaced MS-DOS, Clipper and other xBase-based programming languages largely fell by the wayside. Clipper enthusiasts can continue to develop in xBase and compile programs that include CH files using Harbour and the Harbour MiniGUI.
How do I open a CH file?
Because CH files are text files, you can open them with any text editor, such as Microsoft Notepad (Windows), Apple TextEdit (Mac), or Github Atom (cross-platform). However, if you want to actually develop or compile an xBase-based program and use a CH file in that program, you should download and install Harbour or the Harbour MiniGUI. These development environments allow developers to create xBase-based programs.