On Thu, Feb 20, 2014 at 2:16 AM, Jonathan Wakely <jwakely....@gmail.com> wrote: > On 13 February 2014 20:47, Patrick Palka wrote: >> On a related note, would a patch to officially enable >> -Wmissing-declarations in the build process be well regarded? > > What would be the advantage?
A missing declaration for an extern function definition likely means that the function should be marked static instead, so enabling the flag would help detect whether a function should otherwise be given static linkage. Isn't this especially important in libstdc++, where accidentally exposing an internal symbol in the library's ABI means having to keep the symbol around until the next ABI bump? > >> Since >> -Wmissing-prototypes is currently enabled, I assume it is the >> intention of the GCC devs to address these warnings, and that during >> the transition from a C to C++ bootstrap compiler a small oversight >> was made (that -Wmissing-prototypes is a no-op against C++ source >> files). > > The additional safety provided by -Wmissing-prototypes is already > guaranteed for C++. > > In C a missing prototype causes the compiler to guess, probably > incorrectly, how to call the function. > > In C++ a function cannot be called without a previous declaration and > the linker will notice if you declare a function with one signature > and define it differently. Good point.. -Wmissing-declarations does not provide additional safety to C++. Really the only benefit to the flag is the static thing mentioned above.
