Hello, I'm trying to create an FFI wrapper for an Adobe Framemaker
automation library.  Here's the sample code in C that I'm trying to re-
create in Ruby:

	IntT j = 0;
	UIntT i;
	F_IntsT attributes;
	F_StringsT strings;

	/* Get name of each FontFamily and display it based on whether it is
visible
	 * in PGF Designer. */
	strings = F_ApiGetStrings(0, FV_SessionId, FP_FontFamilyNames);
	attributes = F_ApiGetInts(0, FV_SessionId, FP_FontFamilyAttributes);
	for(i=0; i<attributes.len; i++){
		j = attributes.val[i];
		if(j & FV_FAMILY_VISIBLE)
		F_Printf(NULL,"Family %s\n", strings.val[i]);
	}


F_StringsT looks like this:

typedef struct {
	UIntT len;
	StringT *val;
} F_StringsT;

StringT is defined as unsigned char *, so I think I'm trying to read
an array of pointers to strings, or unsigned char **.

Right now I'm just trying to get the strings in Ruby:

# in my FFI module FM:
class FStringsT < FFI::Struct
    layout :len, :int,
      :val, :pointer
  end

attach_function :FApiGetStrings,[:int,:int,:int], FStringsT.by_value

# in my script:
strings = FM.FApiGetStrings(0, FM.FVSessionId, FM.FPFontFamilyNames)
attributes = FM.FApiGetInts(0, FM.FVSessionId,
FM.FPFontFamilyAttributes)

puts strings[:len], attributes[:len] # => 337
strptr = strings[:val].read_pointer()
if !( strptr.null? )
  puts strptr # =>  #<FFI::Pointer:0x3bd0e04>
  sa = strptr.get_array_of_string(0,strings[:len]).compact # => causes
seg fault
  puts sa
end

I found the get_array_of_string example on the wiki.  Any ideas what I
might be doing wrong?

Thanks!
Drew