dangling reference in convert(Ptr{Uint8},String)

[JeffBezanson]

This conversion (currently at string.jl:47)

convert(::Type{Ptr{Uint8}}, s::String) = convert(Ptr{Uint8}, bytestring(s))

returns a pointer to an unreferenced object. This is a memory bug.

When bytestring(s) occurs as an argument in ccall, this is not a problem since ccall is designed to keep a reference to the original un-converted arguments.

[StefanKarpinski]

Should we maybe only define this operation for cconvert and not for convert?

[JeffBezanson]

Yes, cconvert(::Type{Ptr{Uint8}}, s::String) = bytestring(s) would work the same as in the Ptr{Ptr{T}} case, since ccall internally knows how to convert ByteStrings.