time.h File Reference
Standard clock support. More...
Go to the source code of this file.
Classes | |
| struct | timespec |
| A time value with up to nanosecond precision. More... | |
| struct | tm |
| Structure representing a date in the Gregorian calendar. More... | |
Macros | |
| #define | CLOCKS_PER_SEC ((clock_t)CPU_TIMER_HZ) |
| The number of ticks on the monotonic clock per second. | |
| #define | TIMER_ABSTIME 1 |
| Flag to indicate that a timespec should be treated as an absolute, rather than relative, time. | |
Typedefs | |
| typedef enum __clockid_t | clockid_t |
| ID for a clock. Only monotonic and 'realtime' (wall clock) are supported. | |
| typedef uint64_t | clock_t |
| Type for holding time. | |
Enumerations | |
| enum | __clockid_t { CLOCK_MONOTONIC , CLOCK_REALTIME , CLOCK_THREAD_CPUTIME_ID , CLOCK_PROCESS_CPUTIME_ID = CLOCK_THREAD_CPUTIME_ID } |
| ID for a clock. Only monotonic and 'realtime' (wall clock) are supported. More... | |
Functions | |
| static clock_t | clock (void) |
| Returns the amount of CPU time (in units defined by CLOCKS_PER_SEC) that are accounted to the current thread (POSIX specifies 'process' here, but CHERIoT RTOS does not have an directly analogous abstraction). | |
| __cheriot_libcall int | clock_gettime (clockid_t clockID, struct timespec *outTime) |
| Retrieve the time from the specified clock as a timespec. | |
| __cheriot_compartment ("wall_clock") int clock_update_wall_clock(TimeoutArgument timeout) | |
| Update the wall-clock time from available time sources. | |
| __cheriot_libcall time_t | time (time_t *tloc) |
| POSIX-compatible time() implementation. | |
| time_t __cheriot_libcall | timegm (struct tm *time) |
| Convert a struct tm to a time_t. | |
| struct tm *__cheriot_libcall | gmtime_r (const time_t *__restrict timer, struct tm *__restrict result) |
| C standard function to calculate a human-readable UTC date and time in a struct tm from a UNIX timestamp passed indirectly as timer. | |
| static struct tm * | gmtime (const time_t *timer) |
| C standard function to calculate a human-readable UTC date and time in a struct tm from a UNIX timestamp. | |
Detailed Description
Standard clock support.
Definition in file time.h.
Macro Definition Documentation
◆ CLOCKS_PER_SEC
| #define CLOCKS_PER_SEC ((clock_t)CPU_TIMER_HZ) |
◆ TIMER_ABSTIME
| #define TIMER_ABSTIME 1 |
Typedef Documentation
◆ clock_t
| typedef uint64_t clock_t |
Type for holding time.
The CLOCKS_PER_SEC macro defines the value in this type that corresponds to one second. This rate is SoC-specific.
Enumeration Type Documentation
◆ __clockid_t
| enum __clockid_t |
ID for a clock. Only monotonic and 'realtime' (wall clock) are supported.
| Enumerator | |
|---|---|
| CLOCK_MONOTONIC | The monotonic clock. This is zero at system start and increments at a fixed rate. |
| CLOCK_REALTIME | The wall-clock time. This clock's value is meaningful only if clock_update_wall_clock has been called at least once and there is at least one working clock source in the system. |
| CLOCK_THREAD_CPUTIME_ID | CPU time consumed by the current thread, since boot time. This clock is equivalent to CLOCK_MONOTONIC if the scheduler is not compiled with support for accounting. Add --scheduler-accounting=y to your build configuration line to enable this. |
| CLOCK_PROCESS_CPUTIME_ID | CPU time consumed by the current 'process'. This value is defined by POSIX, but CHERIoT RTOS does not have a direct equivalent of a process and so this value is equivalent to CLOCK_THREAD_CPUTIME_ID, with all of the attendant caveats. |
Function Documentation
◆ clock()
|
inlinestatic |
Returns the amount of CPU time (in units defined by CLOCKS_PER_SEC) that are accounted to the current thread (POSIX specifies 'process' here, but CHERIoT RTOS does not have an directly analogous abstraction).
Note: If scheduler accounting is not enabled, this API will return the total elapsed uptime instead. Add --scheduler-accounting=y to your build configuration line to enable this.
Definition at line 99 of file time.h.
References thread_elapsed_cycles_current().
◆ clock_gettime()
Retrieve the time from the specified clock as a timespec.
If clockID is CLOCK_REALTIME, the returned value is meaningful only if clock_update_wall_clock has been called at least once and there is at least one working clock source in the system.
◆ gmtime()
|
inlinestatic |
C standard function to calculate a human-readable UTC date and time in a struct tm from a UNIX timestamp.
This uses an internal buffer that is invalidated on each subsequent call and is not thread safe. gmtime_r should be used instead.
Definition at line 207 of file time.h.
References gmtime_r().
◆ gmtime_r()
◆ time()
| __cheriot_libcall time_t time | ( | time_t * | tloc | ) |
POSIX-compatible time() implementation.
Returns the time in seconds since the UNIX epoch.
This value is meaningful only if clock_update_wall_clock has been called at least once and there is at least one working clock source in the system.
References time().
Referenced by Timeout::elapse(), time(), timegm(), and Timeout::Timeout().
◆ timegm()
| time_t __cheriot_libcall timegm | ( | struct tm * | time | ) |
Convert a struct tm to a time_t.
This is intended to be compatible with the BSD extension and is equivalent to the POSIX mktime with a UTC locale.
The tm_wday and tm_yday fields are ignored as inputs. Other fields may be out of range, for example an hour of -1 means hour 22 in the previous day, a day of 40 in a month with 31 days means day 9 in the next month, and so on.
The values of the tm_wday and tm_yday fields will be set on successful completion.
NOTE: UNIX time stamps do not include leap seconds. If a leap second (the 60th second at the end of June or December in a year that contains one) is specified in time, it will be treated as an overflow and the result of this function will be off by one.
References time().
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