There are some significant changes to the behavior of ccall and cfunction that are in the process of being merged into master. Most of it is backwards-compatible, although there a few important changes to note.
If you are not a package maintainer, you may want to wait a week before attempting to upgrade to the latest master. Or stick with the v0.3 stable release. The task-driver PR is: https://github.com/JuliaLang/julia/pull/7906 You can find a short description of the update in the NEWS: https://github.com/JuliaLang/julia/pull/7906/files?short_path=8312ad0#diff-8312ad0561ef661716b48d09478362f3 The calling-c-and-fortran-code section of the manual also has had a substantial rewrite to be generally more informative and helpful: https://github.com/JuliaLang/julia/blob/jn/ccall3/doc/manual/calling-c-and-fortran-code.rst There are two primary sources of API breakage that you may encounter: - most convert(Ptr{T}, ::Any) methods have been moved to become methods of unsafe_convert - the cfunction API now interprets its list of argument types in the same manner as ccall. isbits types and Any are unaffected by this change. other types now need to be wrapped in a Ref{...} declaration - incorrectly declared ccall arguments may suddenly cease to work. for example, a bitstype is distinct from a structtype on some platforms, so passing a WrapperType declared immutable WrapperType; child::Cint; end to an argument expecting an int on the C side will stop working correctly. this also applies to return values and cfunction.
