#include <rw/rwtime.h> RWTime a; // Construct with current time
Class RWTime represents a time, stored as the number of seconds since 00:00:00 January 1, 1901 GMT. See Section 5 of the User's Guide for how to set the time zone for your compiler. Failure to do this may result in GMT times being wrong.
Output formatting is done using an RWLocale object. The default locale formats according to U.S. conventions.
Note that because the default constructor for this class creates an instance holding the current date and time, constructing a large array of RWTime may be slow.
RWTime v[5000]; // Figures out the current time 5000 times
Those with access to the C++ Standard Library-based versions of the Tools.h++ template collections should consider the following:
// Figures out the current time just once: RWTValOrderedVector<RWTime> v(5000, RWTime());
Thanks to the smart allocation scheme of the standard collections, the above declaration will result in only one call to the default constructor followed by 5000 invocations of the copy constructor. In the case of RWTime, the copy constructor amounts to an assignment of one long to another, resulting in faster creation than the simple array.
Simple
This example constructs a current time, and the time when Daylight-Saving Time starts in the year 1990. It then prints them out.
#include <rw/rwtime.h>
#include <rw/rwdate.h>
#include <rw/rstream.h>
main(){
RWTime t; // Current time
RWTime d(RWTime::beginDST(1990, RWZone::local()));
cout << "Current time: " << RWDate(t) << " " << t <<
endl;
cout << "Start of DST, 1990: " << RWDate(d) << " " << d <<
endl;
}
Program output
Current time: 03/22/91 15:01:40 Start of DST, 1990: 05/01/90 02:00:00
RWTime();
Default constructor. Constructs a time with the present time.
RWTime(const RWTime&);
Copy constructor.
RWTime(unsigned long s);
Constructs a time with s seconds since 00:00:00 January 1, 1901 GMT. If s==0, an invalid time is constructed. Note that for small s this may be prior to January 1, 1901 in your time zone.
The compiler can parse 0 as either an integer or a pointer. Since there is also a constructor which takes a pointer (to struct tm), if you want to construct a time from the unsigned long value 0, you will have to be explicit:
RWTime earlyTime((unsigned long)0);
RWTime(unsigned hour, unsigned minute, unsigned second=0,
const RWZone& zone = RWZone::local());
Constructs a time with today's date, and the specified hour, minute, and second, relative to the time zone zone, which defaults to local time.
RWTime(const RWDate& date, unsigned hour = 0,
unsigned minute = 0,unsigned second = 0,
const RWZone& = RWZone::local());
Constructs a time for a given date, hour, minute, and second, relative to the time zone zone, which defaults to local time. Note that the maximum RWTime is much sooner than maximum RWDate. (In fact, it is on Feb. 5, 2037 for platforms with 4-byte longs.) This is a consequence of the fact that RWTime counts seconds while RWDate only deals with full days.
RWTime(const struct tm*, const RWZone& = RWZone::local());
Constructs a time from the tm_year, tm_mon, tm_mday, tm_hour, tm_min, and tm_sec components of the struct tm argument. These components are understood to be relative to the time zone zone, which defaults to local time. Note that the numbering of months and years in a struct tm differs from that used in RWTime arguments.
RWTime(const RWDate& date, const RWCString& str,
const RWZone& zone = RWZone::local(),
const RWLocale& locale = RWLocale::global());
Constructs a time for the given date, extracting the time from the string str. The string str should contain only the time. The time is understood to be relative to the time zone zone, which defaults to local time. The specified locale is used for formatting information . Use function isValid() to check the results. Note: not all time string errors can be detected by this function.
RWTime& operator=(const RWTime&);
Assignment operator.
RWTime operator++();
Prefix increment operator. Add one second to self, then return the results.
RWTime operator--();
Prefix decrement operator. Subtract one second from self, then return the results.
RWTime operator++(int);
Postfix increment operator. Add one second to self, returning the initial value.
RWTime operator--(int);
Postfix decrement operator. Subtract one second from self, returning the initial value.
RWTime& operator+=(unsigned long s);
Add s seconds to self, returning self.
RWTime& operator-=(unsigned long s);
Subtract s seconds from self, returning self.
RWCString
asString(char format = '\0',const RWZone& = RWZone::local(),
const RWLocale& = RWLocale::global()) const;
Returns self as a string, formatted by the RWLocale argument, with the time zone adjusted according to the RWZone argument. Formats are as defined by the standard C library function strftime(). The default format is the date followed by the time: "%x %X". The exact format of the date and time returned is dependent upon the implementation of strftime() available. For more information, look under RWLocale.
RWCString
asString(char* format,const RWZone& = RWZone::local(),
const RWLocale& = RWLocale::global()) const;
Returns self as a string, formatted by the RWLocale argument, with the time zone adjusted according to the RWZone argument. Formats are as defined by the standard C library function strftime().
RWBoolean between(const RWTime& a, const RWTime& b) const;
Returns TRUE if RWTime is between a and b, inclusive.
size_t binaryStoreSize() const;
Returns the number of bytes necessary to store the object using the global function
RWFile& operator<<(RWFile&, const RWTime&);
int compareTo(const RWTime* t) const;
Comparison function, useful for sorting times. Compares self to the RWTime pointed to by t and returns:
0 if self == *t;
1 if self > *t;
-1 if self < *t;
void extract(struct tm*,const RWZone& = RWZone::local()) const;
Fills all members of the struct tm argument, adjusted to the time zone specified by the RWZone argument. If the time is invalid, the struct tm members are all set to -1. Note that the encoding of struct tm members is different from that used in RWTime and RWDate functions.
unsigned hash() const;
Returns a suitable hashing value.
unsigned hour(const RWZone& zone = RWZone::local()) const;
Returns the hour, adjusted to the time zone specified.
unsigned hourGMT() const;
Returns the hour in GMT.
RWBoolean isDST(const RWZone& zone = RWZone::local()) const;
Returns TRUE if self is during Daylight-Saving Time in the time zone given by zone, FALSE otherwise.
RWBoolean isValid() const;
Returns TRUE if this is a valid time, FALSE otherwise.
RWTime max(const RWTime& t) const;
Returns the later time of self or t.
RWTime min(const RWTime& t) const;
Returns the earlier time of self or t.
unsigned minute(const RWZone& zone = RWZone::local()) const;
Returns the minute, adjusted to the time zone specified.
unsigned minuteGMT() const;
Returns the minute in GMT.
unsigned second() const;
Returns the second; local time or GMT.
unsigned long seconds() const;
Returns the number of seconds since 00:00:00 January 1, 1901 GMT.
static RWTime
beginDST(unsigned year,
const RWZone& zone = RWZone::local());
Return the start of Daylight-Saving Time (DST) for the given year, in the given time zone. Returns an "invalid time" if DST is not observed in that year and zone.
static RWTime endDST(unsigned year, const RWZone& = RWZone::local());
Return the end of Daylight-Saving Time for the given year, in the given time zone. Returns an "invalid time" if DST is not observed in that year and zone.
static unsigned hash(const RWTime& t);
Returns the hash value of t as returned by t.hash().
static RWTime now();
Returns the present time.
RWTime operator+(const RWTime& t, unsigned long s); RWTime operator+(unsigned long s, const RWTime& t);
Returns an RWTime s seconds greater than t.
RWTime operator-(const RWTime& t, unsigned long s);
Returns an RWTime s seconds less than t.
RWBoolean operator<(const RWTime& t1, const RWTime& t2);
Returns TRUE if t1 is less than t2.
RWBoolean operator<=(const RWTime& t1, const RWTime& t2);
Returns TRUE if t1 is less than or equal to t2.
RWBoolean operator>(const RWTime& t1, const RWTime& t2);
Returns TRUE if t1 is greater than t2.
RWBoolean operator>=(const RWTime& t1, const RWTime& t2);
Returns TRUE if t1 is greater than or equal to t2.
RWBoolean operator==(const RWTime& t1, const RWTime& t2);
Returns TRUE if t1 is equal to t2.
RWBoolean operator!= (const RWTime& t1, const RWTime& t2);
Returns TRUE if t1 is not equal to t2.
ostream& operator<<(ostream& s, const RWTime& t);
Outputs the time t on ostream s, according to the locale imbued in the stream (see class RWLocale), or by RWLocale::global() if none.
//istream& //operator>>(istream&, RWTime&);
We have deliberately omitted this overloaded shift operator. [4]
RWvostream& operator<<(RWvostream&, const RWTime& t); RWFile& operator<<(RWFile&, const RWTime& t);
Saves RWTime t to a virtual stream or RWFile, respectively.
RWvistream& operator>>(RWvistream&, RWTime& t); RWFile& operator>>(RWFile&, RWTime& t);
Restores an RWTime into t from a virtual stream or RWFile, respectively, replacing the previous contents of t.