The Vala Programming Language

Vala is a programming language mainly targeted at GNOME developers.

Its syntax is inspired by C# (and thus, indirectly, by Java). But unlike C# and Java, Vala does not attempt to provide memory safety: Vala is compiled to C, and the C code is compiled with GCC using typical compiler flags. Basic operations like integer arithmetic are directly mapped to C constructs. As a results, the recommendations in Defensive Coding in C apply.

In particular, the following Vala language constructs can result in undefined behavior at run time:

  • Integer arithmetic, as described in Recommendations for Integer Arithmetic.

  • Pointer arithmetic, string subscripting and the substring method on strings (the string class in the glib-2.0 package) are not range-checked. It is the responsibility of the calling code to ensure that the arguments being passed are valid. This applies even to cases (like substring) where the implementation would have range information to check the validity of indexes. See Recommendations for Pointers and Array Handling

  • Similarly, Vala only performs garbage collection (through reference counting) for GObject values. For plain C pointers (such as strings), the programmer has to ensure that storage is deallocated once it is no longer needed (to avoid memory leaks), and that storage is not being deallocated while it is still being used (see Use-after-free errors).