diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/unix/sysv/linux/clock.c | 36 |
1 files changed, 16 insertions, 20 deletions
diff --git a/sysdeps/unix/sysv/linux/clock.c b/sysdeps/unix/sysv/linux/clock.c index 5268d33..16036bd 100644 --- a/sysdeps/unix/sysv/linux/clock.c +++ b/sysdeps/unix/sysv/linux/clock.c @@ -1,4 +1,5 @@ -/* Copyright (C) 1991-2013 Free Software Foundation, Inc. +/* Return the time used by the program so far (user time + system time). + Copyright (C) 1991-2013 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -19,26 +20,21 @@ #include <time.h> #include <unistd.h> -/* Return the time used by the program so far (user time + system time). */ +#if CLOCKS_PER_SEC != 1000000l +# error "CLOCKS_PER_SEC should be 1000000" +#endif + clock_t clock (void) { - struct tms buf; - long clk_tck = __sysconf (_SC_CLK_TCK); - - /* We don't check for errors here. The only error the kernel - returns is EFAULT if the value cannot be written to the struct we - pass a pointer to. Otherwise the kernel returns an `unsigned - long' value which is the number of jiffies since system start. - But this number can be negative (when read as `long') when the - system is up for some time. Ignoring errors should therefore - have no negative impacts but solve the problem. */ - __times (&buf); - - return - (clk_tck <= CLOCKS_PER_SEC) - ? ((unsigned long) buf.tms_utime + buf.tms_stime) * (CLOCKS_PER_SEC - / clk_tck) - : ((unsigned long) buf.tms_utime + buf.tms_stime) / (clk_tck - / CLOCKS_PER_SEC); + struct timespec ts; + + /* clock_gettime shouldn't fail here since CLOCK_PROCESS_CPUTIME_ID is + supported since 2.6.12. Check the return value anyway in case the kernel + barfs on us for some reason. */ + if (__glibc_unlikely (__clock_gettime (CLOCK_PROCESS_CPUTIME_ID, &ts) != 0)) + return (clock_t) -1; + + return (ts.tv_sec * CLOCKS_PER_SEC + + ts.tv_nsec / (1000000000 / CLOCKS_PER_SEC)); } |