Kevin, adding const in front gave me this error:
type: ccall: expected Symbol, got Ptr{None}
while loading In[3], in expression starting on line 3
Luckily João, your code finally worked for me! So if I understand this
correctly, the problem was that we were originally passing a Ptr to ccall,
when all I should've been doing is passing a string declared as a constant?
On Monday, September 1, 2014 4:46:07 PM UTC-4, João Felipe Santos wrote:
>
> I'm sorry, there was a mistake in my example. The dlopen step should be
> used just to check whether the file is accessible as a shared library.
> ccall expects the full path to the .dylib file in case the library is not
> at a "standard" location.
>
> Do something like this instead:
>
> const liboauth = "/path/to/liboauth"
> (dlopen_e(liboauth) == C_NULL) && error("Unable to load shared library
> at the given path.")
> b64d = ccall((:oauth_sign_hmac_sha1, liboauth), Ptr{Uint8},
> (Ptr{Uint8}, Ptr{Uint8}), testurl, testkey)
> println(bytestring(b64d))
>
> Note that you have to use bytestring and not string. string will create a
> string from printing the pointer (which will show something like Ptr{Uint8}
> @0x0000012345). bytestring converts a C string from a pointer to an
> ASCIIString, which is what you want.
>
> --
> João Felipe Santos
>
>
> On Mon, Sep 1, 2014 at 4:24 PM, Randy Zwitch <[email protected]
> <javascript:>> wrote:
>
>> Thanks for the suggestions everyone. Unfortunately, neither the code from
>> Ivar nor João worked for me.
>>
>> liboauth = dlopen("/usr/local/lib/liboauth.dylib")
>>
>> Out[8]:
>>
>> Ptr{Void} @0x00007fdc665c5ca0
>>
>> In [9]:
>>
>> function oauth_sign_hmac_sha1(m::String,k::String)
>>
>> res =
>> ccall((:oauth_sign_hmac_sha1,liboauth),Ptr{Uint8},(Ptr{Uint8},Ptr{Uint8}),m,k)
>>
>> if res == C_NULL
>>
>> error("oauth_sign_hmac_sha1 failed")
>>
>> end
>>
>> return string(res)
>>
>> end
>>
>>
>>
>> testurl =
>> "GET&http%3A%2F%2Fphotos.example.net%2Fphotos&file%3Dvacation.jpg%26oauth_consumer_key%3Ddpf43f3p2l4k3l03%26oauth_nonce%3Dkllo9940pd9333jh%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1191242096%26oauth_token%3Dnnch734d00sl2jdk%26oauth_version%3D1.0%26size%3Doriginal"
>>
>> testkey = "kd94hf93k423kf44&pfkkdhi9sl3r4s00"
>>
>> oauth_sign_hmac_sha1(testurl, testkey)
>>
>> type: oauth_sign_hmac_sha1: in ccall: first argument not a pointer or
>> valid constant expression, expected DataType, got Type{(Any...,)}
>> while loading In[9], in expression starting on line 11
>>
>> in oauth_sign_hmac_sha1 at In[9]:2
>>
>>
>>
>>
>> testurl =
>> "GET&http%3A%2F%2Fphotos.example.net%2Fphotos&file%3Dvacation.jpg%26oauth_consumer_key%3Ddpf43f3p2l4k3l03%26oauth_nonce%3Dkllo9940pd9333jh%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1191242096%26oauth_token%3Dnnch734d00sl2jdk%26oauth_version%3D1.0%26size%3Doriginal"
>>
>> testkey = "kd94hf93k423kf44&pfkkdhi9sl3r4s00"
>>
>> b64d = ccall((:oauth_sign_hmac_sha1, liboauth), Ptr{Uint8}, (Ptr{Uint8},
>> Ptr{Uint8}), testurl, testkey)
>>
>> bytestring(b64d)
>>
>> type: anonymous: in ccall: first argument not a pointer or valid constant
>> expression, expected DataType, got Type{(Any...,)}
>> while loading In[10], in expression starting on line 3
>>
>> in anonymous at no file
>>
>>
>> Does this mean I compiled the library wrong? When I did the 'make' step,
>> after it was complete, I did 'make installcheck' and the 3 tests reported
>> that they completed successfully.
>>
>> At a higher level, I like Isaiah's suggestion of doing this process by
>> hand to really get to understanding what is going on. Is there an eaier
>> external library that one of you could suggest that I could use to walk
>> through the entire process? I've done the examples in the manual using
>> :clock and :getenv and understand what is going on, so now I want to work
>> with a user-installed library to make sure I really get the process. I
>> started with OAuth to see if I could make something usable to work with my
>> Twitter package, but maybe it's not the best starting place.
>>
>>
>> On Monday, September 1, 2014 10:47:22 AM UTC-4, João Felipe Santos wrote:
>>
>>> You need to do ccalls using Ptr{Uint8}. What you can do actually is wrap
>>> the Clang.jl-generated functions with your own functions with an
>>> alternative signature, and then convert from ASCIIString to Ptr{Uint8}.
>>> Note that you probably will need to do it anyways to wrap the return types,
>>> since you probably do not want to work with pointers from Julia :)
>>>
>>> In that specific example, if m and k are ASCIIStrings, conversions will
>>> be done automatically:
>>>
>>> testurl = "GET&http%3A%2F%2Fphotos.example.net%2Fphotos&file%
>>> 3Dvacation.jpg%26oauth_consumer_key%3Ddpf43f3p2l4k3l03%26oauth_
>>> nonce%3Dkllo9940pd9333jh%26oauth_signature_method%
>>> 3DHMAC-SHA1%26oauth_timestamp%3D1191242096%26oauth_token%
>>> 3Dnnch734d00sl2jdk%26oauth_version%3D1.0%26size%3Doriginal"
>>> testkey = "kd94hf93k423kf44&pfkkdhi9sl3r4s00"
>>> b64d = ccall((:oauth_sign_hmac_sha1, liboauth), Ptr{Uint8},
>>> (Ptr{Uint8}, Ptr{Uint8}), testurl, testkey)
>>>
>>> Note that b64d here will be a Ptr{Uint8}, which you can convert to a
>>> Julia string by using bytestring(b64d).
>>>
>>> --
>>> João Felipe Santos
>>>
>>>
>>>
