time.c

来自「Newlib 嵌入式 C库 标准实现代码」· C语言 代码 · 共 54 行

/*
FUNCTION
<<time>>---get current calendar time (as single number)

INDEX
	time

ANSI_SYNOPSIS
	#include <time.h>
	time_t time(time_t *<[t]>);

TRAD_SYNOPSIS
	#include <time.h>
	time_t time(<[t]>)
	time_t *<[t]>;

DESCRIPTION
<<time>> looks up the best available representation of the current
time and returns it, encoded as a <<time_t>>.  It stores the same
value at <[t]> unless the argument is <<NULL>>.

RETURNS
A <<-1>> result means the current time is not available; otherwise the
result represents the current time.

PORTABILITY
ANSI C requires <<time>>.

Supporting OS subroutine required: Some implementations require
<<gettimeofday>>.
*/

/* Most times we have a system call in newlib/libc/sys/.. to do this job */

#include <_ansi.h>
#include <reent.h>
#include <sys/types.h>
#include <sys/time.h>

time_t
_DEFUN (time, (t),
	time_t * t)
{
  struct timeval now;

  if (_gettimeofday_r (_REENT, &now, NULL) >= 0)
    {
      if (t)
	*t = now.tv_sec;
      return now.tv_sec;
    }
  return -1;
}