Version Check in C Extension

ruby-talk
1

Hello!

How can I check for the Ruby version inside a C extension? I found some
constants in version.h, but I don't think that file is included via
ruby.h and it has a very common name that may conflicts with similar
files in other projects. So, I don't think it is wise to include
version.h in a Ruby extension.

Is there another way to check if the extension gets compiled with Ruby
1.8 or 1.9?

Regards,
Elias

2

How can I check for the Ruby version inside a C extension?

Try to avoid to test the ruby version, but rather test the functionality
that you want in extconf.rb.

For example

moulon% ruby -rmkmf -ve 'have_func("rb_frame_this_func")'
ruby 1.8.4 (2005-12-24) [i486-linux]
checking for rb_frame_this_func()... no
moulon%

moulon% ./ruby -rmkmf -ve 'have_func("rb_frame_this_func")'
ruby 1.9.0 (2006-07-14) [i686-linux]
checking for rb_frame_this_func()... yes
moulon%

Guy Decoux

3

In your extconf.rb file construct a -D option from the RUBY_VERSION constant:

VERSION_NUMBER = '0x'+RUBY_VERSION.tr('.','')
$CPPFLAGS = "-DRUBY_VERSION=#{VERSION_NUMBER}"

···

elias.athanasopoulos@gmail.com wrote:

Hello!

How can I check for the Ruby version inside a C extension? I found some
constants in version.h, but I don't think that file is included via
ruby.h and it has a very common name that may conflicts with similar
files in other projects. So, I don't think it is wise to include
version.h in a Ruby extension.

Is there another way to check if the extension gets compiled with Ruby
1.8 or 1.9?

Regards,
Elias

4

Hello!

ts wrote:

> How can I check for the Ruby version inside a C extension?

Try to avoid to test the ruby version, but rather test the functionality
that you want in extconf.rb.

For example

moulon% ruby -rmkmf -ve 'have_func("rb_frame_this_func")'
ruby 1.8.4 (2005-12-24) [i486-linux]
checking for rb_frame_this_func()... no
moulon%

moulon% ./ruby -rmkmf -ve 'have_func("rb_frame_this_func")'
ruby 1.9.0 (2006-07-14) [i686-linux]
checking for rb_frame_this_func()... yes
moulon%

Right. This is the problem I have to deal with. My extension uses
rb_frame_last_func() which is subsituted with rb_frame_this_func() in
1.9. So, I have to alter the actual code to use rb_frame_last_func() or
rb_frame_this_func() according to the ruby version installed in the
system.

So, checking in the Makefile will not help.

Regards,
Elias

5

So, checking in the Makefile will not help.

This is bdb

static VALUE
bdb_indexes(int argc, VALUE *argv, VALUE obj)
{
    VALUE indexes;
    int i;

#if HAVE_RB_ARY_VALUES_AT
    rb_warn("Common#%s is deprecated; use Common#values_at",
#if HAVE_RB_FRAME_THIS_FUNC
            rb_id2name(rb_frame_this_func()));
#else
            rb_id2name(rb_frame_last_func()));
#endif
#endif

Guy Decoux

6

Hello!

ts wrote:

This is bdb

static VALUE
bdb_indexes(int argc, VALUE *argv, VALUE obj)
{
    VALUE indexes;
    int i;

#if HAVE_RB_ARY_VALUES_AT
    rb_warn("Common#%s is deprecated; use Common#values_at",
#if HAVE_RB_FRAME_THIS_FUNC
            rb_id2name(rb_frame_this_func()));
#else
            rb_id2name(rb_frame_last_func()));
#endif
#endif

Thanx!

Regards,
Elias

7

Hello!

ts wrote:

static VALUE
bdb_indexes(int argc, VALUE *argv, VALUE obj)
{
    VALUE indexes;
    int i;

#if HAVE_RB_ARY_VALUES_AT
    rb_warn("Common#%s is deprecated; use Common#values_at",
#if HAVE_RB_FRAME_THIS_FUNC
            rb_id2name(rb_frame_this_func()));
#else
            rb_id2name(rb_frame_last_func()));
#endif
#endif

Again, in my Debian box:

elathan@velka:/usr/lib/ruby/1.9/i486-linux> find . | xargs grep HAVE_RB
./config.h:#define HAVE_RB_FD_INIT 1
./intern.h:#if defined(NFDBITS) && defined(HAVE_RB_FD_INIT)
./intern.h:#define HAVE_RB_DEFINE_ALLOC_FUNC 1
elathan@velka:/usr/lib/ruby/1.9/i486-linux>

Should I generate the macro HAVE_RB_FRAME_THIS_FUNC in the Makefile? I
thought Ruby 1.9 had it by default defined in its internals.

Regards,
Elias

8

Should I generate the macro HAVE_RB_FRAME_THIS_FUNC in the Makefile? I
thought Ruby 1.9 had it by default defined in its internals.

Part of extconf.rb for bdb

["rb_frame_this_func", "rb_block_proc", "rb_io_stdio_file"].each do |f|
   if have_func(f)
      $CFLAGS += " -DHAVE_#{f.upcase}"
   end
end

["insert", "values_at"].each do |f|
   print "checking for Array##{f}... "
   if .respond_to?(f)
      puts "yes"
      $CFLAGS += " -DHAVE_RB_ARY_#{f.upcase}"
   else
      puts "no"
   end
end

Guy Decoux

9

Hi,

At Mon, 28 Aug 2006 22:15:09 +0900,
Athanasopoulos wrote in [ruby-talk:211102]:

Should I generate the macro HAVE_RB_FRAME_THIS_FUNC in the Makefile?

have_func does it.

I thought Ruby 1.9 had it by default defined in its internals.

No.

···

--
Nobu Nakada

10

have_func does it.

yes, but create_header must be called

Guy Decoux

11

Hi,

At Mon, 28 Aug 2006 23:41:58 +0900,
ts wrote in [ruby-talk:211133]:

> have_func does it.

yes, but create_header must be called

have_func stores the macros in $defs, and they are directly
placed in Makefile as CPPFLAGS, unless create_header is called.

···

--
Nobu Nakada