On Sat, Mar 30, 2019 at 12:25 AM Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx> wrote: > Sparse will warn on casts removing the address space of a pointer > if the destination type is not unsigned long. But the special role > of 'unsigned long' is not explained in the man page. > > So, add a small explanation in the description of -Waddress-space. > > Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx> > --- > sparse.1 | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/sparse.1 b/sparse.1 > index fae6196bf..a94bf0109 100644 > --- a/sparse.1 > +++ b/sparse.1 > @@ -41,9 +41,11 @@ Sparse allows an extended attribute > on pointers, which designates a pointer target in address space \fIid\fR (an > identifier or a constant integer). > With \fB\-Waddress\-space\fR, Sparse treats pointers with > -identical target types but different address spaces as distinct types. To > -override this warning, such as for functions which convert pointers between > -address spaces, use a type that includes \fB__attribute__((force))\fR. > +identical target types but different address spaces as distinct types and > +will warn accordingly. Sparse will also warn on casts which remove the address > +space (unless the target type is \fBunsigned long\fR and \fB-Wcast\-from\-as\fR > +is not given). To override these warnings, use a type that includes > +\fB__attribute__((force))\fR. I wonder whether another approach to this might be to have a different warning string when the target type is a number and isn't `unsigned long`? It seems to me that a self-explaining error message is preferable to a clarification in the manpage.
