ID Number: Q49501
5.10 6.00 6.00a 6.00ax
MS-DOS
Summary:
The ftime() function takes a pointer to a timeb structure as its only
parameter and has no return value. Ftime() calculates the current time
and returns it by modifying the timeb structure. The structure
contains the following elements in the given order:
Name Type Description
---- ---- -----------
time time_t(long) The time in seconds since 00:00:00 Greenwich
mean time, January 1, 1970. This time is
calculated under MS-DOS by calling Int 21,
function 2Ah (Get Date), converting the
results to seconds, and adding the current
time, which is also converted to seconds.
millitm USHORT Fraction of a second in milliseconds. This
value is actually not milliseconds on most
systems. On most IBM PCs and compatibles, the
clock speed is not fast enough to compute
milliseconds, or indeed, hundredths of
seconds. The ftime function calls interrupt
21, function 2Ch (under MS-DOS), which returns,
among other information, the seconds in
hundredths. The hundredths information is an
estimation based on the clock speed, which is
approximately 18.2 ticks per second on most
PCs. The hundredths value is then multiplied
by ten to get the millisecond value.
timezone short The difference in minutes, moving westward,
between Greenwich mean time and local time.
This is equal to the global variable
timezone, from a call to the tzset function.
dstflag short This flag is nonzero if daylight savings
time (DST) is currently in effect for the local
time zone. This is done by a call to the
internal function _isindst. This function
takes a timeb structure as a parameter and
returns an integer flag. This is the rule for
years before 1987; a time is in DST if it is
on or after 02:00:00 on the last Sunday in
April and before 01:00:00 on the last Sunday
in October. This is the rule for years
starting with 1987; a time is in DST if it
is on or after 02:00:00 on the first Sunday
in April and before 01:00:00 on the last
Sunday in October. (See tzset for more
information on DST.)
Other sources of information include the version 5.1 "Microsoft C for
the MS-DOS Operating System: Run-Time Library Reference," and the
online help for Microsoft C version 6.0.
Additional reference words: 5.00 5.10 6.00 6.00a 6.00ax