#ifndef VLIBC_SYS_TIMES_H
#define VLIBC_SYS_TIMES_H

/*
 * vlibc — <sys/times.h>.
 *
 * Process CPU-time accounting in clock ticks. times() and struct tms are
 * XSI [CX] in POSIX.1-2008 (glibc gates them behind _XOPEN_SOURCE, not
 * _POSIX_C_SOURCE), so the whole surface sits at level 2 — nothing here is
 * POSIX.1-2008 base:
 *
 *   Level 2 (muslmimic): times, struct tms.
 *
 * clock_t is the scalar tick type owned by <sys/types.h> (typedef long
 * clock_t; <time.h> pulls it from the same place for clock()); this header
 * includes that one rather than re-typedefing clock_t. The unit of every
 * times() figure is the tick: CLK_TCK per second, the fixed x86_64 USER_HZ
 * constant of 100 that todo 32's sysconf(_SC_CLK_TCK) reports (defined
 * once, in src/misc/sysconf.c).
 *
 * struct tms mirrors the x86_64 kernel's __kernel_tms exactly: four longs
 * in the same order (tms_utime, tms_stime, tms_cutime, tms_cstime), which
 * is why src/sys/times.c hands the struct straight to SYS_times. The kernel
 * writes all four words on every successful call, so no field is optional.
 *
 * The declaration carries no intent attribute: times() performs a syscall
 * with side effects and reports failures through errno, so const/pure
 * would be unsound (see the rationale in <sys/time.h>).
 */

#include <vlibc/features.h>

#include <sys/types.h> /* clock_t */

#ifdef __cplusplus
extern "C" {
#endif

#if VLIBC_LEVEL_GE(2)
/* Level 2 (muslmimic): XSI process-CPU-time accounting. */

/*
 * CPU-time accounting for the calling process and its waited-for children,
 * measured in clock ticks (CLK_TCK per second). tms_utime and tms_stime
 * are the user and system CPU time of the calling process; tms_cutime and
 * tms_cstime are the user and system CPU time consumed by children that
 * have been waited for (all four zeroed before any child is waited on).
 */
struct tms
{
    clock_t tms_utime;  /* user CPU time of the calling process */
    clock_t tms_stime;  /* system CPU time of the calling process */
    clock_t tms_cutime; /* user CPU time of waited-for children */
    clock_t tms_cstime; /* system CPU time of waited-for children */
};

/*
 * Store the process CPU-time accounting through buf and return the number
 * of clock ticks since an arbitrary fixed point in the past (the Linux
 * kernel reports ticks since boot). Return (clock_t)-1 with errno set when
 * buf points outside the address space.
 */
clock_t
times(struct tms *buf);

#endif /* VLIBC_LEVEL_GE(2) */

#ifdef __cplusplus
}
#endif

#endif /* VLIBC_SYS_TIMES_H */