> On 29 Nov 2021, at 10:10, Guillermo Polito <guillermopol...@gmail.com> wrote:
>
> Hi Gerry,
>
> I think the point of Tomaz is that an FFI method can only have a single
> #ffiCall: statement.
> In your example, what you can do is to split your method in two methods:
>
> First a method with the mapping (following the idea of Tomaz but using libc)
>
> FFITutorial>>getHostNameInto: hostName ofLenght: length
>> ^self ffiCall: #( int gethostname(char *hostName, int length) ) library:
>> 'libc.so.6'.
>
> And then have a second method that calls this one:
>
> FFITutorial>>getHostName
>
> | nameBuffer |
>
> nameBuffer := ByteArray new: 256.
>
> self getHostNameInto: nameBuffer ofLenght: 256.
>
> ^nameBuffer asString
>
> Notice that converting the byte array buffer to string will only work by
> chance if the called function returns characters encoded in ascii.
> In Pharo strings are Unicode characters where each character is a unicode
> code-point.
In general #utf8Decoded is better than #asString since UTF-8 includes 7-bit
ASCII. It will fail when the native encoding is one of the simpler byte
encodings, like Latin1 (or iso-8859-1), though.
> The best thing is to read the documentation of the library and check the
> encoding of the string that is put in the buffer to decode it accordingly,
> for example from utf8.
>
> G
>
>
>> El 29 nov 2021, a las 0:56, Gerry Weaver <ger...@compvia.com> escribió:
>>
>> Hi,
>>
>> Thanks for the example. Unfortunately, it doesn't work on Linux.
>>
>> Thanks,
>> Gerry
>>
>>
>> From: Tomaž Turk <tomaz.t...@ef.uni-lj.si>
>> Sent: Sunday, November 28, 2021 11:39 AM
>> To: Any question about pharo is welcome <pharo-users@lists.pharo.org>
>> Subject: [Pharo-users] Re: uFFI provide buffer to C
>>
>> Hi,
>>
>> try with this:
>>
>> FFITutorial>>getHostNameInto: hostName ofLenght: length
>> ^self ffiCall: #( int gethostname(char *hostName, int length) ) library:
>> 'Ws2_32.dll'. "... on Windows"
>>
>> From Playground, you can then do:
>>
>> | name len |
>> len := 50.
>> name:= ByteArray new: len.
>> FFITutorial new getHostNameInto: name ofLenght: len.
>> name inspect.
>>
>> I hope this helps.
>>
>> Best wishes,
>> Tomaz
>
