tcc_global: Declare a global variable getter

In Rtinycc: Builds the 'TinyCC' Command-Line Interface and Library for 'C' Scripting in 'R'

Declare a global variable getter

Description

Register a global C symbol so the compiled object exposes getter/setter functions ⁠global_<name>_get()⁠ and ⁠global_<name>_set()⁠.

Usage

tcc_global(ffi, name, type)

Arguments

ffi	A tcc_ffi object
name	Global symbol name
type	FFI type for the global (scalar types only)

Details

Globals are limited to scalar FFI types. Array types are rejected. Scalar conversions follow the same rules as wrapper arguments:

• Integer inputs (i8, i16, i32, u8, u16) must be finite and within range; NA values error.

• Large integer types (i64, u32, u64) are mediated through R numeric (double). Values must be integer-valued and within range; for i64/u64 only exact integers up to $2^53$ are accepted.

• Getter wrappers for i64/u64 warn when the stored value exceeds R's exact integer range for numeric vectors.

• bool rejects NA logicals.

Ownership notes:

• ptr globals store the raw address from an external pointer. If the external pointer owns memory, keep it alive; otherwise the pointer may be freed while the global still points to it.

• cstring globals store a borrowed pointer to R's string data (UTF-8 translation). Do not free it; for C-owned strings prefer a ptr global and manage lifetime explicitly (e.g., with tcc_cstring()).

Value

Updated tcc_ffi object (for chaining)

Note

Global helpers are generated inside the compiled TCC unit. Recompiling creates a new instance of the global variable; existing compiled objects continue to refer to their own copy.

Examples

ffi <- tcc_ffi() |>
  tcc_source("int global_counter = 7;") |>
  tcc_global("global_counter", "i32") |>
  tcc_compile()
ffi$global_global_counter_get()

Rtinycc documentation built on April 28, 2026, 1:07 a.m.