Run the C preprocessor on file using the provided compiler — preprocess

This function runs the configured C compiler with the -E preprocessor flag and returns the combined preprocessed output as a single string.

Usage

preprocess_header(file, cc = r_cc(), ccflags = NULL, ...)

Arguments

file

Path to a header file to preprocess.

cc

(Character) Compiler command to use. If NULL, resolved via r_cc().

ccflags

(Character) Additional flags to pass to the compiler.

...

Arguments passed on to preprocess_headers

dir: Directory where header files will be searched.
recursive: Logical; whether to search recursively.
pattern: File name pattern(s) used to identify header files.

Value

Character scalar with the preprocessed output of file.

Examples

if (FALSE) { # \dontrun{
# Check for a compiler before running an example that invokes the preprocessor
rcc <- treesitter.c::r_cc()
if (nzchar(rcc)) {
  rcc_prog <- strsplit(rcc, "\\s+")[[1]][1]
  if (nzchar(Sys.which(rcc_prog))) {
    tmp <- tempfile("hdr3")
    dir.create(tmp)
    path <- file.path(tmp, "p.h")
    writeLines(c("#define TYPE int", "TYPE foo(TYPE x);"), path)
    out <- preprocess_header(path)
    grepl("int foo\\(", out)
  } else {
    message("Skipping preprocess example: compiler not found on PATH")
  }
}
} # }