tf2/tf2_src/devtools/swigwin-1.3.34/Lib/ruby/file.i

// FILE *
%{
#ifdef __cplusplus
extern "C" {
#endif
#include "rubyio.h"
#ifdef __cplusplus
}
#endif
%}

%typemap(in) FILE *READ {
    OpenFile *of;
    GetOpenFile($input, of);
    rb_io_check_readable(of);
    $1 = GetReadFile(of);
    rb_read_check($1);
}

%typemap(in) FILE *READ_NOCHECK {
    OpenFile *of;
    GetOpenFile($input, of);
    rb_io_check_readable(of);
    $1 = GetReadFile(of);
}

%typemap(in) FILE *WRITE {
    OpenFile *of;
    GetOpenFile($input, of);
    rb_io_check_writable(of);
    $1 = GetWriteFile(of);
}