— Scheme Procedure: current-time
— C Function: scm_current_time ()

Return the number of seconds since 1970-01-01 00:00:00 UTC, excluding leap seconds.

— Scheme Procedure: gettimeofday
— C Function: scm_gettimeofday ()

Return a pair containing the number of seconds and microseconds since 1970-01-01 00:00:00 UTC, excluding leap seconds. Note: whether true microsecond resolution is available depends on the operating system.

— Scheme Procedure: localtime sse [zone]
— C Function: scm_localtime (sse, zone) |1 |1 |0

Return an object representing the broken down components of sse, the seconds-since-epoch (from, e.g., current-time). The time zone for the calculation is optionally specified by zone (a string), otherwise the TZ environment variable or the system default is used.

— Scheme Procedure: gmtime sse
— C Function: scm_gmtime (sse)

Return an object representing the broken down components of sse, the seconds-since-epoch (from, e.g., current-time). The values are calculated for UTC.

— Scheme Procedure: mktime bdt [zone]
— C Function: scm_mktime (bdt, zone) |1 |1 |0

bdt is an object representing broken down time and zone is an optional time zone specifier (otherwise the TZ environment variable or the system default is used).

Return a pair: the car is a corresponding integer time value like that returned by current-time; the cdr is a broken down time object, similar to bdt but with normalized values.

— Scheme Procedure: tzset
— C Function: scm_tzset ()

Initialize the timezone from the TZ environment variable or the system default. It's not usually necessary to call this procedure since it's done automatically by other procedures that depend on the timezone.

— Scheme Procedure: strftime template bdt
— C Function: scm_strftime (template, bdt)

Format the broken-down time bdt using template. bdt is an object with time components in the form returned by localtime or gmtime. template is a string which can include formatting specifications introduced by a % character. The formatting of month and day names is dependent on the current locale. Return the formatted string.

See Formatting Date and Time.

— Scheme Procedure: strptime template string
— C Function: scm_strptime (template, string)

Perform the reverse action to strftime, parsing string according to the specification supplied in template. The interpretation of month and day names is dependent on the current locale.

Return a pair. The car has an object with time components in the form returned by localtime or gmtime, but the time zone components are not usefully set. The cdr reports the number of characters from string which were used for the conversion.

— Variable: internal-time-units-per-second

The value of this variable is the number of time units per second reported by the following procedures.

— Scheme Procedure: times
— C Function: scm_times ()

Return an object with information about real and processor time. The following procedures accept such an object as an argument and return a selected component:

tms:clock

The current real time, expressed as time units relative to an arbitrary base.

tms:utime

The CPU time units used by the calling process.

tms:stime

The CPU time units used by the system on behalf of the calling process.

tms:cutime

The CPU time units used by terminated child processes of the calling process, whose status has been collected (e.g., using waitpid).

tms:cstime

Similarly, the CPU times units used by the system on behalf of terminated child processes.

— Scheme Procedure: get-internal-real-time
— C Function: scm_get_internal_real_time ()

Return the number of time units since the interpreter was started.

— Scheme Procedure: get-internal-run-time
— C Function: scm_get_internal_run_time ()

Return the number of time units of processor time used by the interpreter. Both "system" and "user" time are included but subprocesses are not.