Re: [Valgrind-developers] Re: Problems with Valgrind CVS and Suse 9.0

[Nicholas N. <nj...@ca...>]

On Thu, 30 Oct 2003, Jeremy Fitzhardinge wrote:

> No.  strace is (somewhat) lying - the syscall is returning -2, not -1.
> If you were using libc, then open() would return -1 and set errno to 2
> (ENOENT).  But since we're going straight to the kernel and don't have
> errno, VG_(open) is directly returning the negative error code (-2 ==
> ENOENT).

The different views of syscalls -- glibc's view vs. the kernel's view --
has tripped me up before.  Generally, the kernel returns a negative error
value, and then glibc puts that in errno (but positive), and returns -1
from the call.  There are some cases where the kernel vs. glibc difference
is bigger -- I think mmap, brk and getcwd are examples.

N