Messages in this thread | | | Date | Thu, 8 Nov 2007 16:15:51 +1100 | From | Paul Mackerras <> | Subject | Re: compat_sys_times() bogus until jiffies >= 0. |
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David Miller writes:
> I can't see where x86 is doing this though, so perhaps for x86 > glibc does make the negative value check. But I doubt it is > checking the range 0x80000000-0xffffffff, otherwise mmap() would > be busted.
At least for the INTERNAL_SYSCALL macro in glibc, the error check is:
#define INTERNAL_SYSCALL_ERROR_P(val, err) \ ((unsigned int) (val) >= 0xfffff001u)
in sysdeps/unix/sysv/linux/i386/sysdep.h. Similarly the PSEUDO macro in that file does a cmpl $-4095,%eax to test for error. (There is also a PSEUDO_NOERRNO which doesn't test for error.)
So the convention on (32-bit) x86 is that -4095 .. -1 are error values, and other values are successful return values.
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