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

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

-----Original Message-----
> Date: Tue, 06 Nov 2018 13:29:19 +0100
> From: Thomas Monjalon <thomas@monjalon.net>
> To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> Cc: "dev@dpdk.org" <dev@dpdk.org>, "Jacob, Jerin"
>  <Jerin.JacobKollanukkaran@cavium.com>, "stable@dpdk.org" <stable@dpdk.org>
> Subject: Re: [dpdk-dev] [PATCH] eal: fix build issue
> 
> 
> 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);
}


 

> 
>