Re: [dpdk-dev] [PATCH] eal: fix build issue

[Thomas Monjalon <thomas@monjalon.net>]

06/11/2018 14:31, Jerin Jacob:
> From: Thomas Monjalon <thomas@monjalon.net>
> > 06/11/2018 12:45, Jerin Jacob:
> > > Some toolchain has fls() definition in string.h as argument type int,
> > > which is conflicting uint32_t argument type.
> > >
> > > /export/dpdk.org/lib/librte_eal/common/rte_reciprocal.c:47:19:
> > > error: conflicting types for ‘fls’
> > >  static inline int fls(uint32_t x)
> > >                   ^~~
> > >
> > > /opt/marvell-tools-201/aarch64-marvell-elf/include/strings.h:59:6:
> > > note: previous declaration of ‘fls’ was here
> > >  int  fls(int) __pure2;
> > >
> > > FreeBSD string.h also has fls() with argument as int type.
> > > https://www.freebsd.org/cgi/man.cgi?query=fls&sektion=3
> > >
> > > Fixing the conflict by renaming internal function as __fls
> > 
> > Why not rte_fls? Would it be more future proof?
> 
> Agreed. There are two instance of fls in dpdk code base now,
> 
> 1) lib/librte_eal/common/rte_reciprocal.c takes uint32_t
> 2) drivers/net/fm10k/fm10k_ethdev.c has macro, used with uint16_t as
> argument.
> 
> Should we make it as macro or follow libc prototype where argument is
> int.
> 
> Something like below,
> 
> static inline int
> rte_fls(int x)
> {
> 	return (x == 0) ? 0 : sizeof(x) * 8 - __builtin_clz(x);
> }

I tend to think that using uint32_t parameter would be more useful in DPDK.