/* clock.c - clock file for time.h */ /* Copyright 1992-2001 Wind River Systems, Inc. */ /* modification history -------------------- 01d,05oct01,dcb Fix SPR 9814 and SPR 7736. Change document to explain why VxWorks always returns -1 for this function. 01c,05feb93,jdi documentation cleanup for 5.1. 01b,20sep92,smb documentation additions 01a,25jul92,smb written. */ /* DESCRIPTION INCLUDE FILE: time.h SEE ALSO: American National Standard X3.159-1989 NOMANUAL */ #include "vxWorks.h" #include "time.h" /****************************************************************************** * * clock - determine the processor time in use (ANSI) * * This routine returns the implementation's best approximation of * the processor time used by the program since the beginning of an * implementation-defined era related only to the program invocation. * To determine the time in seconds, the value returned by clock() * should be divided by the value of the macro CLOCKS_PER_SEC. If the * processor time used is not available or its value cannot be * represented, clock() returns -1. * * NOTE: * This routine always returns -1 in VxWorks. VxWorks does not track * per-task time or system idle time. There is no method of determining * how long a task or the entire system has been doing work. tickGet() * can be used to query the number of system ticks since system start. * clock_gettime() can be used to get the current clock time. * * INCLUDE FILES: time.h * * RETURNS: -1 * * SEE ALSO: tickGet(), clock_gettime() */ clock_t clock (void) { return ((clock_t) -1); }
