While the "modern" (actually, 1970s, from ML) approach with option types is vastly superior, modern C compilers do let you declare that function parameters shou

While the "modern" (actually, 1970s, from ML) approach with option types is vastly superior, modern C compilers do let you declare that function parameters should not be NULL. In GCC or Clang, add __attribute__((nonnull)). There are still issues[1] with this, but it's sufficient for most code. [1] One big issue is that GCC takes this hint and uses it in the optimizer, so you cannot have both a compile time and a run time check for a non-NULL parameter.