date_sunset

Description

mixed date_sunset ( int timestamp [, int format [, float latitude [, float longitude [, float zenith [, float gmt_offset]]]]] )

date_sunset() returns the sunset time for a given day (specified as a timestamp) and location. The latitude, longitude and zenith parameters default to the date.default_latitude, date.default_longitude and date.sunset_zenith configuration options, respectively.

The latitude defaults to North. So, if you want to specify a South value, you must pass a negative value. The same note applies to longitude, which defaults to East.

The gmt_offset parameter is specified in hours.

表格 1. format constants

constant	description	example
SUNFUNCS_RET_STRING	returns the sunset time as string	16:46
SUNFUNCS_RET_DOUBLE	returns the result as float	16.78243132
SUNFUNCS_RET_TIMESTAMP	returns the sunset time as an integer (timestamp)	1095034606

例子 1. date_sunset() example
<?php /* calculate the sunset time for Lisbon, Portugal Latitude: 38.4 North Longitude: 9 West Zenith ~= 90 offset: +1 GMT */ echo date("D M d Y"). ', sunset time : ' .date_sunset(time(), SUNFUNCS_RET_STRING, 38.4, -9, 90, 1); ?>
上例的输出类似于：
Mon Dec 20 2004, sunset time : 18:13