This is the mail archive of the
libc-alpha@sources.redhat.com
mailing list for the glibc project.
Re: Problem with VMware 2.0.4 and glibc 2.2.5
On Wed, Apr 10, 2002 at 09:41:48AM -0700, H . J . Lu wrote:
> On Wed, Apr 10, 2002 at 09:24:58AM -0700, Ulrich Drepper wrote:
> > On Wed, 2002-04-10 at 09:06, H . J . Lu wrote:
> >
> > > It looks like glibc 2.2.5 changed the ABI for nice. Shouldn't we give
> > > it a new version?
> >
> > No, we never do this for bug fixes. If someone depends on a bug instead
> > of reporting it they deserve what they get.
> >
>
> Is that what people get when they read the Linux man pages? On RedHat
> 7.2.93 (Skipjack),
>
> # man 2 nice
> NICE(2) Linux Programmer's Manual NICE(2)
>
> NAME
> nice - change process priority
>
> SYNOPSIS
> #include <unistd.h>
>
> int nice(int inc);
>
> DESCRIPTION
> nice adds inc to the nice value for the calling pid. (A
> large nice value means a low priority.) Only the super-
> user may specify a negative increment, or priority
> increase.
>
> RETURN VALUE
> On success, zero is returned. On error, -1 is returned,
> and errno is set appropriately.
>
>
> It is fine to fix the bug. But in this case, this "feature" is well
> documented. You can't fix the bug by breaking the existing binaries
> written according to the Linux man pages.
The same man page contains also:
Note that the routine is documented in SUSv2 to return the new nice value, while the Linux syscall and
(g)libc (earlier than glibc 2.2.4) routines return 0 on success. The new nice value can be found using get-
priority(2). Note that an implementation in which nice returns the new nice value can legitimately return
-1. To reliably detect an error, set errno to 0 before the call, and check its value when nice returns -1.
which you apparently omitted (the man page is dated back in June 2001).
Furthermore, as it is nice(2) not nice(3) man page, on success zero is
really returned (that's what the kernel does).
Jakub