Messages in this thread | | | Date | Sun, 30 Dec 2001 17:10:41 -0500 | From | Brian Gerst <> | Subject | Re: [PATCH][RFC] global errno considered harmful |
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Ralf Baechle wrote: > > On Sun, Dec 30, 2001 at 02:56:21PM -0500, Jeff Dike wrote: > > > buytenh@gnu.org said: > > > Is there any particular reason we need a global errno in the kernel at > > > all? (which, by the way, doesn't seem to be subject to any kind of > > > locking) > > > > As far as I've been able to tell, no. > > Historically the reason was to make unistd.h usable from userspace. Which > is causing tremendous portability problems so apps better shouldn't think > about using the syscall interface directly. > > > > It makes life for User Mode Linux somewhat more complicated > > > than it could be, and it generally just seems a bad idea. > > > > Yeah. In order for -fno-common to not blow up the UML build (because of the > > clash between libc errno and kernel errno), I had to add -Derrno=kernel_errno > > to all the kernel file compiles. It would be nice to get rid of that wart. > > > > > Referenced patch deletes all mention of a global errno from the > > > kernel > > > > Awesome. This definitely needs to happen. If no one spots any breakage, > > send it in... > > As user application are trying to use unistd.h and expect errno to get > set properly unistd.h or at least it's syscallX macros will have to be > made unusable from userspace or silent breakage of such apps rebuild > against new headers will occur.
Userspace should be using glibc's unistd.h. If it's using the kernel's, it's broken.
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