Dl/loader ptr issue

Ruby
1

I’m having fits with passing pointers to a function I’ve imported via
DL::Importable. I’m wrapping a simple opaque blob library (part of
libdnet). However, the function I’m wrapping doesn’t seem to work as I
expect it to.

 extern "int blob_read(void *blob, void *buf, int size)"

Basically, read the specified amount (size) from the blob, and put it
in buf. return status code. From what I’ve read, I should be able to
wrap this with something akin to:

def read (blob, len)
	ptr = DL.malloc(len)
	ret = Dnet.blob_read(blob, ptr.ref, len)
	return ret.to_s
end

However, I get a EXC_BAD_ACCESS segv duing the to_s call. How should I
be getting access to buf?

My current test is attached. I have validated that the shared object
works as expected, when using dlopen/dlsym in C. (dnet.c works as an
example usage of the C api)

Brian

2

Brian Caswell wrote:

However, the function I’m wrapping doesn’t seem to work as I
expect it to.

extern "int blob_read(void *blob, void *buf, int size)"

…

def read (blob, len)
    ptr = DL.malloc(len)
    ret = Dnet.blob_read(blob, ptr.ref, len)
    return ret.to_s
end

How about using “ptr” instead of “ptr.ref”?

3

On Dec 28, 2005, at 8:20 AM, Takaaki T. wrote:=

end

How about using “ptr” instead of “ptr.ref”?

Thanks!

That worked, though the to_s doesn’t, I needed to_str.

Brian