Vin32

July 17, 2026 ยท View on GitHub

A basic, heuristic-based CLI tool to generate V language bindings from simple Windows C header files.

About

vin32 is a line-by-line parsing utility written in V that helps generate basic V language bindings from Windows API headers (such as windef.h, winuser.h, etc.).

Since it does not use a full AST parser or a C preprocessor (like Clang/LLVM), it relies on string-matching heuristics. It is designed to quickly bootstrap simple Win32 bindings, structures, and constants, though some generated parts may require manual adjustment.

Features

  • Heuristic Parsing: Iterates through sorted .h files to find struct declarations, flat typedefs, and function signatures.
  • Basic Type Mapping: Translates common Win32 types (like DWORD, LPVOID, HWND) to V equivalents (u32, voidptr, etc.) using a static map.
  • Macro Constant Extraction: Identifies simple numeric, hexadecimal, and string #define statements and converts them to pub const.
  • Reserved Keyword Safety: Automatically prefixes fields that clash with V's reserved keywords (such as type) with v_ to prevent syntax errors.
  • Configurable CLI: Allows specifying the input directory, output path, and module name via command-line flags.

Usage

Prerequisites

Command Line Options

Usage: vin32 [flags]

Flags:
  -i, --input <string>      Path to the directory containing C headers
  -o, --output <string>     Path to the output V file (default: win32.v)
  -m, --module <string>     V module name (default: win32)
  -h, --help                Prints help information

Example

To compile and run the tool against a folder of headers:

v cmd/vin32.v
./vin32 -i /path/to/mingw/include -o win32.v -m win32

Known Limitations

This utility is a line-by-line text parser and has several limitations that may require manual post-processing of the generated code:

  • No C Preprocessor: It does not resolve conditional compilation (#ifdef, #ifndef). Code inside inactive or active preprocessor blocks is parsed indiscriminately.
  • Unresolved Types to voidptr: Any C type or structure pointer not found in the static mapping or not yet processed will fall back to voidptr to ensure the generated code compiles.
  • Flattened Unions: C union blocks are currently flattened into standard V struct definitions. This changes the memory layout size and offsets, which can cause silent runtime crashes when passed to Windows APIs. Users must manually add the [union] attribute where necessary.
  • Empty Structs: Structs with complex nested declarations, inline macro functions, or unrecognized syntax may be parsed with empty fields.
  • Function Pointers: Complex function pointers (such as typedef void (*WNDPROC)(...)) are skipped or simplified.

Contributing

If you find a common Win32 pattern that isn't parsed correctly, feel free to open an issue or submit a pull request with the C code snippet and the expected V translation.

License

License