R help - Nov 2018 - Use of C functions inside the DLL object

hello everybody and good night ...
I'm trying to learn how to use a DLL, via "dyn.load" and
".C" inside the R.
I did some testing (below is a part of what I tried) and I could not 
figure out how to do this.
If anyone can give a hint on how to do this manipulation, it would be a 
lot of help!
And thanks in advance for any tip.
Thank you!
Cleber

###

In the pdf explaining the SDK, it has function detail:

FDwfGetVersion(char szVersion[32])
Description: Retrieves the version string. The version string is 
composed of major, minor, and build numbers (i.e.,
?2.0.19?).


##############################################################

### In R, I tried:

 > dwf <- dyn.load("C:\\Windows\\System32\\dwf")
 > is.loaded("FDwfGetVersion")
[1] TRUE
 > result <- .C("FDwfGetVersion", version=as.character() )
 > result
$`version`
character(0)

 > str(result)
List of 1
 ?$ version: chr(0)

#################################

But in Python, I saw that the result is as follows (examples in Python 
are made available by the manufacturer)

#################################

 >>> from ctypes import *
 >>> dwf = cdll.dwf
 >>> version = create_string_buffer(16)
 >>> dwf.FDwfGetVersion(version)
1
 >>> print("DWF Version: "+str(version.value))
DWF Version: 3.8.22
 >>>








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Hello,

You must pass a string with a number of characters large enough to 
accomodate the return value you want. This is one of the shortcomings of 
the .C interface.

The string ?2.0.19? ahs 6 characters, so try

.C("FDwfGetVersion", version = character(6) )


Hope this helps,

Rui Barradas

?s 20:57 de 19/11/2018, Cleber N.Borges via R-help
escreveu:
> .C("FDwfGetVersion", version=as.character() )