GSL error handler also now returns information from

GSL.

Occasionally the extra information from GSL is useful but cannot be
mapped precisely to an existing Julia exception without losing the
information.

The current hacky solution is to simply print the GSLError object to
STDERR using warn(show(GSLError)).

Should probably have a better solution in the future.

src/ConvertGSL.jl

@@ -25,10 +25,12 @@ type GSLError <: Exception
     line :: Cint
 end
 
-show(io::IO, E::GSLError) = print(io, string("GSL Error", strerror(E.errno), " -- ", E.reason, " at ", E.file, ":", E.line))
+show(io::IO, E::GSLError) = print(io, string("GSL Error: ", strerror(E.errno), " -- ", E.reason, " at ", E.file, ":", E.line))
 
 function custom_error_handler(reason::AbstractString, file::AbstractString, line::Integer, errno::Integer)
     if errno == 0; return; end # GSL_SUCCESS
+
+    warn(GSLError(errno, reason, file, line))
     if errno == 1 # GSL_EDOM: input domain error, e.g sqrt(-1)
         throw(DomainError())
     elseif errno == 2 || errno == 16