On Tue, Jun 2, 2020 at 4:21 PM Michael Forney <mfor...@mforney.org> wrote: > > On 2020-06-02, Alexei Starovoitov <alexei.starovoi...@gmail.com> wrote: > > the enum definition of BPF_F_CTXLEN_MASK is certainly within standard. > > I don't think kernel should adjust its headers because some compiler > > is failing to understand C standard. > > This is not true. See C11 6.7.2.2p2: "The expression that defines the > value of an enumeration constant shall be an integer constant > expression that has a value representable as an int." > > You can also see this with gcc if you turn on -Wpedantic and include > it in a way such that warnings are not silenced: > > $ gcc -Wpedantic -x c -c -o /dev/null /usr/include/linux/bpf.h
ISO C forbids zero-size arrays, unnamed struct/union, gcc extensions, empty unions, etc So ? warning: ISO C forbids zero-size array ‘args’ [-Wpedantic] 4095 | __u64 args[0]; warning: ISO C90 doesn’t support unnamed structs/unions [-Wpedantic] 3795 | __bpf_md_ptr(void *, data_end); #define BPF_F_CTXLEN_MASK BPF_F_CTXLEN_MASK will only work as workaround for _your_ compiler. We are not gonna add hacks like this for every compiler.
