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author | Rich Felker <dalias@aerifal.cx> | 2013-05-23 14:31:02 -0400 |
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committer | Rich Felker <dalias@aerifal.cx> | 2013-05-23 14:31:02 -0400 |
commit | 05453b37fc0343e53bc7f332047e901b3e1abb84 (patch) | |
tree | 46aec81077cc8062cb3a63e7a6504d9498bb1d25 /arch/x86_64/syscall_arch.h | |
parent | 1e5eb73545ca6cfe8b918798835aaf6e07af5beb (diff) | |
download | musl-05453b37fc0343e53bc7f332047e901b3e1abb84.tar.gz |
fix overflow behavior of clock() function
per Austin Group interpretation for issue #686, which cites the
requirements of ISO C, clock() cannot wrap. if the result is not
representable, it must return (clock_t)-1. in addition, the old code
was performing wrapping via signed overflow and thus invoking
undefined behavior.
since it seems impossible to accurately check for overflow with the
old times()-based fallback code, I have simply dropped the fallback
code for now, thus always returning -1 on ancient systems. if there's
a demand for making it work and somebody comes up with a way, it could
be reinstated, but the clock() function is essentially useless on
32-bit system anyway (it overflows in less than an hour).
it should be noted that I used LONG_MAX rather than ULONG_MAX, despite
32-bit archs using an unsigned type for clock_t. this discrepency with
the glibc/LSB type definitions will be fixed now; since wrapping of
clock_t is no longer supported, there's no use in it being unsigned.
Diffstat (limited to 'arch/x86_64/syscall_arch.h')
0 files changed, 0 insertions, 0 deletions