From: Paul Brannan <pbrannan@...>
Date: 2001-07-26T03:39:46+09:00
Subject: [ruby-talk:18538] Re: Opening a FILE* in a C extension

One possibility is to use rb_file_open (which itself calls fopen) to open
the file, then use GetReadFile and/or GetWriteFile and/or GetOpenFile to
get the FILE* pointer.  e.g. (untested):

  #include <rubyio.h>
  VALUE io = rb_file_open("foo", "r+);
  OpenFile *open_file;
  FILE *rfp, *wfp;
  GetOpenFile(io, open_file);
  rfp = GetReadFile(open_file);
  wfp = GetWriteFile(open_file);

Normally, rfp and wfp will be the same, but this is not true in the case
of a pipe.  Be forewarned that some of the above function calls can raise
exceptions (specifically rb_file_open and GetOpenFile) so be careful when
using them.

Paul


On Thu, 26 Jul 2001, Brett W. Denner wrote:

> In a C extension, I need to read data from a file using fread.  I also want
> to make sure that the file is closed after the read (even if an exception is
> raised, for example).  What is the best way to do this in Ruby?  Should I
> just use fopen and register the FILE* with Ruby's garbage collection?  Do I
> need to manually fclose all my FILE* pointers?   Or is there a better way to
> make sure my files get closed automatically?
>
> Thanks,
>
> Brett
>
>