c

Imported from JerryLeeSir/NotTerminal (Vendor/GhosttySource/src/terminal/c/AGENTS.md). Install upstream with npx skills add JerryLeeSir/NotTerminal --skill c. Copyright stays with the author.

libghostty-vt C API

• C API must be designed with ABI compatibility in mind
• Zig tagged unions must be converted to C ABI compatible unions via lib.TaggedUnion.
• Any functions must be updated all the way through from here to src/terminal/c/main.zig to src/lib_vt.zig and the headers in include/ghostty/vt.h. Specifically:
  1. Define the function in src/terminal/c/<module>.zig.
  2. Re-export it via a pub const in src/terminal/c/main.zig.
  3. Add an @export call in src/lib_vt.zig with the ghostty_ prefixed symbol name.
  4. Declare it in the corresponding header under include/ghostty/vt/.
• In include/ghostty/vt.h, always sort the header contents by: (1) macros, (2) forward declarations, (3) types, (4) functions

ABI Compatibility

• Prefer opaque pointers for long-lived objects, such as GhosttyTerminal.
• Structs:
  • May contain padding bytes if we're confident we'll never grow beyond a certain size.
  • May use the "sized struct" pattern: an extern struct with size: usize = @sizeOf(Self) as the first field. In the C header, callers use GHOSTTY_INIT_SIZED from types.h to zero-initialize and set the size.