Struct timespec linux NAME top time. CLOCK_GETRES(2) Linux Programmer's Manual CLOCK_GETRES(2) NAME top clock_getres, clock_gettime, clock_settime - clock and time functions SYNOPSIS top #include <time. If specifying an absolute time, this member is the number of seconds since 1970. The function to get the current time in a struct timespec is timespec_get(). 1, linux 4. It aims to provide a comprehensive set of functions with well-defined behaviour that handle all edge cases (e. h> Description Some of the functionality described on this reference page extends the Its struct timespec allows for higher resolution (ns) timestamps than the timeval of SO_TIMESTAMP (ms). C11 doesn't mandate that struct tm has a subsecond component, and strftime() has no way to format subsecond components, etc. Nov 13, 2023 · Overview of clock_gettime () The clock_gettime () function is defined in the POSIX standard and allows accessing timestamps from different clock sources. tv_nsec. clock_nanosleep(2) System Calls Manual clock_nanosleep(2) NAME top clock_nanosleep - high-resolution sleep with specifiable clock LIBRARY top Standard C library (libc, -lc), since glibc 2. h" following error occurs. h header Available on Linux, BSD, Unix, macOS, Solaris, etc. clock_getres(2) System Calls Manual clock_getres(2) NAME top clock_getres, clock_gettime, clock_settime - clock and time functions LIBRARY top Standard C library (libc, -lc), since glibc 2. h> header in C. Mar 29, 2025 · 文章浏览阅读1. However if I compile this without -std=c99 everything works fine. This means it may be removed from a future version of the specification. CLOCK_MONOTONIC with one-second precision. clock_gettime with CLOCK_MONOTONIC clock can be used to avoid this problem. My question is, how does one enable this change to use the 64-bit timespec in the kernel? clock_nanosleep(2) System Calls Manual clock_nanosleep(2) NAME top clock_nanosleep - high-resolution sleep with specifiable clock LIBRARY top Standard C library (libc, -lc), since glibc 2. TIMEVAL(3) Library Functions Manual TIMEVAL(3) NAME timeval, timespec, itimerval, itimerspec, bintime - time structures SYNOPSIS #include <sys/time. (see section Elapsed Time for a description of struct timespec). Conversion between the two is relatively painless; input and output requires a modicum of care (mainly making sure leading zeros for the fractional struct timespec { __kernel_time_t tv_sec; /* seconds */ long tv_nsec; /* nanoseconds */ }; It seems that these definitions are indeed equivalent, but I can't prove it. long int tv_nsec This is the rest of the elapsed time (a fraction of a second), represented as the number of nanoseconds. Its global. NAME ¶ timespec - time in seconds and nanoseconds LIBRARY ¶ Standard C library (libc) SYNOPSIS ¶ #include <time. h> int nanosleep (const struct timespec *req, struct timespec *rem); Feature Test Macro Requirements for glibc (see feature_test_macros (7)): nanosleep (): _POSIX_C_SOURCE >= 199309L Description nanosleep () suspends the execution of the calling thread until either at least the time specified in *req Linux kernel source tree. 21, there is likely a conflict between the struct timespec declared in <parts/time. h(0P) POSIX Programmer's Manual time. SO_TIMESTAMPNS_OLD returns incorrect timestamps after the year 2038 on 32 bit machines. So if you want to wait for 1. GitHub Gist: instantly share code, notes, and snippets. c. h:9: redefinition of `struct Apr 11, 2004 · Detailed Description struct timespec64 is just like the unix 'struct timespec' except that we use a 64-bit signed int to store the seconds. It is declared in time. h> Description Some of the functionality described on this reference page extends the . md)関数によって返される、エポックからの経過時間を表す型である。各メンバ変数は、以下を意味する： Jul 11, 2017 · C11 does specify a struct timespec (§7. Synopsis #include <time. h and has the following members: time_t tv_sec This represents the number of whole seconds of elapsed time. Information about the time zone is returned in the structure pointed at tzp. 18-rc1, x86_64: error: redefinition of 'struct timespec' Hi all, When I tried to compile a sample V4l2 program which includes "/linux/videodev2. 9w次，点赞6次，收藏49次。本文深入探讨了C语言中处理高精度时间的两种结构：struct timespec和struct timeval。通过实例展示了如何使用这些结构来获取纳秒级和微秒级的时间精度，以及如何利用clock_gettime和gettimeofday函数获取系统时间。 C言語標準：構造体struct tm型 より詳細な日付情報が欲しい場合に用いる。 ログに日付出すときに大活躍しました。 Linux Kernel内でも struct timespec と struct tm を変換できます。 。 Jun 24, 2019 · You could find a hardware source (such as the powerpc time base register - see this) - but sounds to me like using jiffies would be good enough - you can get a timespec from jiffies using jiffies_to_timespec(). The various system calls that use the other (older) time formats can generally be emulated in user Nov 10, 2015 · What is the use of tim. POSIX環境で使用できる時間構造体の一つ。 次に紹介する struct timespec と非常によく似た構造体である。 tv_sec time() の戻り値と同値。 tv_usec 範囲は0～999,999 gettimeofday() によってUNIX時間を表現した値が入ったインスタンスが取得できる。 構造体timespec C11で採用されたらしい新しい時間構造体。 Its struct timespec allows for higher resolution (ns) timestamps than the timeval of SO_TIMESTAMP (ms). h>, defines various structures related to time and These macros convert from a timeval (3type) to a timespec (3type) structure, and vice versa, respectively. Always use SO_TIMESTAMPNS_NEW timestamp to always get timestamp in struct __kernel_timespec format. 17 Before glibc 2. 5 seconds, add 1 to timeToWait. The itimerspec structure is described in itimerspec (3type). Provides microsecond or nanosecond resolution (depending on Timeval and timespec In Linux, the current time is maintained by keeping the number of seconds elapsed since midnight of January 01, 1970 (called epoch); the second elements in - Selection from Mastering Linux Kernel Development [Book] Dec 6, 2017 · struct timespec有两个成员，一个是秒，一个是纳秒, 所以最高精确度是纳秒。 一般由函数int clock_gettime (clockid_t, struct timespec *)获取特定时钟的时间，常用如下4种时钟： static inline struct timespec timespec64_to_timespec (const struct timespec64 ts64) { return ts64; } Contributors static inline struct timespec64 timespec_to_timespec64 (const struct timespec ts) { return ts; } Contributors static inline struct itimerspec itimerspec64_to_itimerspec (struct itimerspec64 * its64) { return * its64 Jul 5, 2023 · Answer by Killian Burgess in file "C:\MinGW\include\parts\time. The struct timespec structure represents an elapsed time. In the current version of POSIX, gettimeofday is . Feb 7, 2025 · Implementation may add other members to struct timespec. Under glibc, this is usually long nanosleep (2) - Linux man page Name nanosleep - high-resolution sleep Synopsis #include <time. int tm_year Years since 1900. h header therefore appropriately does this: Previously I was using timespec structure, but windows contains no such thing. h> int clock_getres(clockid_t clockid, struct timespec *res); int clock_gettime(clockid_t clockid, struct timespec *tp); int clock_settime(clockid_t clockid, const struct timespec *tp); Link with -lrt (only for glibc versions Source code of linux/include/linux/time64. int tm_hour Hour [0,23]. You use the correct structure for the system calls you're going to use — struct timeval for gettimeofday() (and select()), and struct timespec for clock_gettime(). tv_nsec, if suitable test macros are defined. The GNU C Library does not provide any functions for computing the difference between two values of type struct timespec or struct timeval. h>, defines various structures related to time and int pthread_mutex_timedlock (pthread_mutex_t *restrict mutex, const struct timespec *restrict abs_timeout); Description The pthread_mutex_timedlock () function shall lock the mutex object referenced by mutex. h" correct the problem. Linux kernel source tree. tv_sec and tim. 1-2001. STANDARDS POSIX. The members include: tv_sec The number of seconds. 1-2008, and, starting with The new_value argument is pointer to an itimerspec structure that specifies the new initial value and the new interval for the timer. const struct timespec *restrict abstime); int pthread_cond_wait(pthread_cond_t *restrict cond, pthread_mutex_t *restrict mutex); DESCRIPTION top The pthread_cond_timedwait () and pthread_cond_wait () functions shall block on a condition variable. Since Linux 2. h(0P) PROLOG top This manual page is part of the POSIX Programmer's Manual. , it has high Sep 18, 2015 · I am trying to convert the start_time of the linux kernel task_struct into nanoseconds. Thanks. For example, you can fine-tune the rate at which the clock “ticks,” and make small adjustments to the current reported calendar time smoothly, by temporarily speeding up or slowing down the clock. 1 Date and time <time. Contribute to torvalds/linux development by creating an account on GitHub. h> struct timespec { time_t tv_sec; long tv_nsec; } Description: The timespec structure specifies a time in seconds and nanoseconds. Another function to suspend the execution of the program is the sleep function which provides low-level resolution suspension but in nanosleep we have the advantage of pausing the program for nanoseconds i. h> int clock_getres(clockid_t clockid, struct timespec *res); int clock_gettime(clockid_t clockid, struct timespec *tp); int clock_settime(clockid_t clockid, const struct timespec *tp); Link with -lrt (only for glibc versions SYNOPSIS top #include <time. The ntp_gettime and ntp_adjtime functions provide an interface to monitor and discipline the system clock. Which means that the clock can go back in time. Sep 4, 2025 · 文章浏览阅读5. or. e. The command GetTickCount does not suffice because it returns time in milliseconds. Here is an example of how to use clock_gettime: [Linux] struct timespec and struct timeval, Programmer Sought, the best programmer technical posts sharing site. 15 2025-05-17 timespec Nov 28, 2017 · Can I get the actual Linux time using this datatype? Brief Background: I am writing a logger utility on embedded device with timestamp resolution in milli/micro seconds. 1-2008. int tm_mday Day of month [1,31]. 1 See also: , Jun 21, 2018 · Bug 86275 - gcc-8. h' and has the following members: Apr 6, 2017 · 4 ALSA depends on types struct timespec and struct timeval. The type is a struct with two fields: Jul 23, 2025 · nanosleep function in C is used to suspend the execution of the program for a specific amount of time for nanoseconds. at) Tue, 18 Jun 1996 09:57:53 +0200 (MET DST) Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] This source say that the '. May 5, 2015 · The current plan is to use the 64-bit version of struct timespec (called, appropriately, struct timespec64 in the kernel, though user space will still see it as simply struct timespec) for almost all time values passed into or out of the kernel. C11, POSIX. h> struct itimerspec { struct timespec it_interval; /* Interval for periodic timer */ struct timespec it_value; /* Initial expiration */ }; DESCRIPTION Describes the initial expiration of a timer, and its interval, in seconds and nanoseconds. Note that both gcc and the IBM Toronto xlC compiler (aka CSet, VisualAge, etc) correctly When I try to compile this on Linux with gcc -std=c99, the compiler complains about not knowing struct timespec. h> header, included by <time. h with a condition for VS builds? May 24, 2019 · `timespec`は、[`timespec_get()`](timespec_get. With nanosleep and precalculating the interval to sleep to reach a given absolute time, you'll fail to wake if the clock is reset and the desired Its struct timespec allows for higher resolution (ns) timestamps than the timeval of SO_TIMESTAMP (ms). h> int clock_getres(clockid_t clockid, struct timespec *_Nullable res); int clock_gettime(clockid_t clockid, struct timespec Jan 10, 2013 · The documentation for this struct was generated from the following file: include/uapi/linux/ time. /usr/include/linux/time. The May 28, 2015 · struct timespec works the same way except that instead of microseconds it's offset (tv_nsec) is stored in nanosecond units. int tm_isdst Daylight Savings flag. at) Tue, 18 Jun 1996 09:57:53 +0200 (MET DST) Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] Sep 20, 2010 · This can be achieved using the clock_gettime function. The function can be is in the <time. Have a read of this. c to copy data between the two types: Oct 17, 2019 · 文章浏览阅读1. Would anyone happen to know something that is as identical to timespec as possible? In particular, all interfaces returning a ‘ struct timeval ’ or ‘ struct timespec ’ have been replaced because the tv_sec member overflows in year 2038 on 32-bit architectures. h — time types SYNOPSIS top #include <time. Each of the substructures of the itimerspec structure is a timespec (3) structure that allows a time value to be specified in seconds and nanoseconds. timespec GetTimeSpecValue(unsigned long milisec) { struct timespec req; NAME timespec - time in seconds and nanoseconds LIBRARY Standard C library (libc) SYNOPSIS #include <time. The system clock can be modified by other processes. h> int sem_timedwait(sem_t *restrict sem, const struct timespec *restrict strptime(3) Library Functions Manual strptime(3) NAME top strptime - convert a string representation of time to a time tm structure LIBRARY top Standard C library (libc, -lc) SYNOPSIS top #define _XOPEN_SOURCE /* See feature_test_macros(7) */ #include <time. Calculate diff of two struct timespec. ag. My question is: is there a robust way to resolve this redefinition? Links to discussions on this problem are also highly appreciated. The function clock_getres () finds the resolution (precision) of the specified clock clk_id, and, if res is non-NULL, stores it in the struct timespec pointed to by res. The nanosecond components of each timestamp are available via names of the form st_atim. tv_sec and add 500000000 to timeToWait. The itimerspec structure is defined as follows: struct timespec { time_t tv_sec; /* Seconds */ long tv_nsec; /* Nanoseconds */ }; struct itimerspec { struct timespec Thomas Gschwind (tom@create. 27. TIME_UTC is always a supported time base, and is the only time base supported on Linux. Classification: POSIX 1003. The application shall ensure that these functions are called with mutex locked by the calling Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. The timespec type can be used to store either a time interval or absolute time. Prior to C23, tv_nsec was long. Feb 7, 2022 · How to convert this into a struct timespec so I can compare with the st_atim, st_mtim, and st_ctim struct timespec 's returned from the stat () function? This post talks about strptime and sscanf, and I also found strftime, but all these convert to a struct time_t or struct tm or integer values. I want to see which struct timespec value is the closest to the time_t value. int tm_yday Day of year [0,365]. The time and resolution in this time base are the same as those retrieved by clock_gettime (CLOCK_REALTIME, res) and clock_getres (CLOCK_REALTIME, tp), respectively. This is especially useful for writing interfaces that receive a type, but are implemented with calls to functions that receive the other one. I have tried following code for the same. Along with "storage size of times Linux kernel source tree. Application writers are encouraged to use the clock_gettime function instead of gettimeofday. clock_gettime () and gettimeofday () return a struct timespec (seconds and nanoseconds) and struct timeval (seconds and microseconds), respectively, and are therefore capable of returning more precise times. 15 2025-05-17 time_t Nov 16, 2025 · TIMEVAL(3) Library Functions Manual TIMEVAL(3) NAME timeval, timespec, itimerval, itimerspec, bintime - time structures SYNOPSIS #include <sys/time. Data Type: struct timespec ¶ The struct timespec structure represents an elapsed time. h linux v6. h> DESCRIPTION top Some of the Pages that refer to this page: timespec (3type), time_t (3type), TIMEVAL_TO_TIMESPEC (3) The gettimeofday function returns the current calendar time as the elapsed time since the epoch in the struct timeval structure indicated by tp. org Linux man-pages 6. h and has the following members: The number of whole seconds elapsed since the epoch (for a simple calendar time) or since some other starting point (for an elapsed time). h> char *strptime(const char *restrict s, const char *restrict format, struct tm *restrict tm); DESCRIPTION top The strptime () function In particular, all interfaces returning a ‘struct timeval’ or ‘struct timespec’ have been replaced because the tv_sec member overflows in year 2038 on 32-bit architectures. tv_sec' field in timespec structure gives " integral number of seconds elapsed since the start of the UNIX epoch, on… Jun 3, 2013 · 上次讲了alarm后，大致看了一下内核的时间表示，所以就记录一下。一、时间的表示方法：Linux内核中表示时间的结构体和数据类型有5种：struct timeval; struct timespec; struct timezone; struct tm; time_t; struct rtc_ti CLOCK_GETRES(2) Linux Programmer's Manual CLOCK_GETRES(2) NAME top clock_getres, clock_gettime, clock_settime - clock and time functions SYNOPSIS top #include <time. Its struct timespec allows for higher resolution (ns) timestamps than the timeval of SO_TIMESTAMP (ms). Negative values are allowed in the tv_sec and/or tv_usec field of timespec structures, tv_usec is always relative to tv_sec, so mixing positive and negative values will NAME timespec - time in seconds and nanoseconds LIBRARY Standard C library (libc) SYNOPSIS #include <time. int tm_min Minutes [0,59]. In particular, all interfaces returning a 'struct timeval' or 'struct timespec' have been replaced because the tv_sec member overflows in year 2038 on 32-bit architectures. h> struct timespec { time_t tv_sec; /* Seconds */ /* */ tv_nsec; /* Nanoseconds [0, 999'999'999] */ }; DESCRIPTION Describes times in seconds and nanoseconds. The times () function is also capable of more precision than time () as it returns a value in clock The structure timespec is used to specify intervals of time with nanosecond precision. The following sketch implements a function suitable for use in a context where the timespec structure is required for a conditional timeout: static void example (struct timespec *spec, time_t minutes) { timespec: overview of system data types Command to display timespec manual in Linux: $ man 3 timespec recvmmsg(2) System Calls Manual recvmmsg(2) NAME top recvmmsg - receive multiple messages on a socket LIBRARY top Standard C library (libc, -lc) SYNOPSIS top #define _GNU_SOURCE /* See feature_test_macros(7) */ #include <sys/socket. tv_nsec The number of nanoseconds. 17). Mar 17, 2019 · I want to convert milliseconds into timespec structure used by GNU Linux. Here is one way to do this calculation by hand. The question is: Is there a standard way to convert between these two? NAME clock_getres, clock_gettime, clock_settime - clock and time functions SYNOPSIS #include <time. Updated file timestamps are set to the greatest value supported by the filesystem that is not greater than the specified time. h> int recvmmsg(int sockfd, struct mmsghdr msgvec[. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. Nanosecond timestamps were standardized in POSIX. h> #include <time. tv_nsec in the following? How can I sleep execution for 500000 microseconds? Feb 7, 2025 · 1) Modifies the timespec object pointed to by ts to hold the current calendar time in the time base base. 16-r on KDAB Codebrowser Jun 17, 2019 · Hi, I tried to compile this in VS2019 and 2017 and it gives following error: error C2011: 'timespec': 'struct' type redefinition Do we have to add #define HAVE_STRUCT_TIMESPEC in pthread. How wou Jul 30, 2020 · The names differ between the implementations, for example compat_timespec for the 32-bit one and timespec for the 64-bit one. The <time. Under glibc, this is usually long, and long long on X32. Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. h>) which is compatible with POSIX struct timespec and supports nanosecond resolution. It is declared in `time. Some of them, like gettimeofday, will get time from the system clock. It is specified in <time. Here some pieces of code from the linux kernel used in the Raspberry Pi OS: There are explicit conversion routines in compat. ,Do please note, that if you are mixing a stock pre-built pthreads-w32 library along with mingwrt-3. This should adequately cover dates in the distant future as well as the distant past, as long as they're not more than a couple dozen times the age of the universe. Next: Setting and Adjusting the Time, Up: Calendar Time [Contents] [Index] Apr 8, 2022 · A struct timespec has another field called tv_nsec which specifies the nanosecond portion. It can be safely down-cast to any concrete 32-bit integer type for processing. This information is conveyed in a timespec (3) structure. h> int clock_getres(clockid_t clockid, struct timespec *_Nullable res); int clock_gettime(clockid_t clockid, struct timespec /* * Kernel time accessors */ unsigned long get_seconds (void); struct timespec64 current_kernel_time64 (void); /* does not take xtime_lock */ struct timespec time typestime. h>struct itimerspec {struct timespec it_interval; /* Interval for periodic timer */ struct timespec it_value; /* Initial expiration */ }; time. Along with "storage size of times The advantages of clock_nanosleep over nanosleep are: You can specify an absolute time to sleep until rather than an interval to sleep. Correctness of calculations with struct timespec Ask Question Asked 11 years, 9 months ago Modified 10 years, 9 months ago Jan 10, 2013 · ns_to_timespec - Convert nanoseconds to timespec : the nanoseconds value to be converted Returns the timespec representation of the nsec parameter. NAME top pmtimespecNow, pmtimespecInc, pmtimespecDec, pmtimespecAdd, pmtimespecSub, pmtimespecToReal, pmtimespecFromReal, pmPrintHighResStamp - helper routines for time stored as a struct timespec Mar 4, 2017 · I have seen this solution but I am getting the same errors. Userland will then continue to use struct timespec, but its tv_sec member will be 64-bits. negative values) in a sensible manner. The type of tv_nsec is longlong on some platforms, which is conforming only since C23. This library provides functions for working with timespec structures. int tm_wday Day of week [0,6] (Sunday =0). It works even on peculiar operating systems where the tv_sec member has an unsigned type. 5. h> and has the form struct timespec { clock_getres(2) System Calls Manual clock_getres(2) NAME top clock_getres, clock_gettime, clock_settime - clock and time functions LIBRARY top Standard C library (libc, -lc), since glibc 2. DESCRIPTION top Describes times in seconds and nanoseconds. The following sketch implements a function suitable for use in a context where the timespec structure is required for a conditional timeout: static void example (struct timespec *spec, time_t minutes) { struct timeval elapsed; (void)gettimeofday (&elapsed, NULL It can be stressed that the traditional UNIX timeval and timespec structures represent elapsed time, measured by the system clock. Feb 20, 2016 · 321) Although a struct timespec object describes times with nanosecond resolution, the available resolution is system dependent and may even be greater than 1 second. 4w次。本文介绍了Linux中的两种常用时间结构struct timespec和struct timeval，并详细解释了如何使用clock_gettime和gettimeofday函数来获取系统当前时间。 Its struct timespec allows for higher resolution (ns) timestamps than the timeval of SO_TIMESTAMP (ms). This time structure stores time-related information, specifically, the seconds and nanoseconds components. h> int clock_nanosleep(clockid_t clockid, int flags, const struct timespec *t, struct timespec *_Nullable remain); Feature Oct 28, 2017 · 1. Here‘s a quick overview: Specifies current time using struct timespec – seconds + nanoseconds Accessible via time. はじめに clock_gettime ()で時刻を取得し時刻を ナノ秒 で表示するサンプルです。時刻取得といえばgettimeofday ()ですが、 POSIX ではgettimeofdayは廃止予定で、clock_gettime ()の利用を推奨しているので、こちらを利用しています。 After researching this a bit, it seems that the solution is to get the kernel to use struct timespec64 internally. Jul 11, 2017 · C11 does specify a struct timespec (§7. h). Under glibc, this is usually long Mar 18, 2024 · Within this function, we declare a variable ts of type struct timespec. n], unsigned int n, int flags, struct timespec *timeout); DESCRIPTION top The recvmmsg () system call is an NAME itimerspec - interval for a timer with nanosecond precision LIBRARY Standard C library (libc) SYNOPSIS #include <time. h> void TIMEVAL_TO_TIMESPEC (struct timeval *tv, struct timespec *ts); void TIMESPEC_TO_TIMEVAL (struct timeval *tv, struct timespec *ts); DESCRIPTION The <sys/time. h Since Linux 2. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up- to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7. tv_nsec is of an implementation-defined signed type capable of holding the specified range. h - Man Page time types Prolog This manual page is part of the POSIX Programmer's Manual. Definition at line 377 of file time. NAME top TIMEVAL_TO_TIMESPEC, TIMESPEC_TO_TIMEVAL - convert between time structures Nov 29, 2011 · It uses strftime(), which works with struct timespec just as well as with struct timeval because all it cares about is the number of seconds, which both provide. POSIX. NAME top sem_timedwait — lock a semaphore SYNOPSIS top #include <semaphore. Should I just compare the seconds and ignore the nanosecon In particular, all interfaces returning a ‘ struct timeval ’ or ‘ struct timespec ’ have been replaced because the tv_sec member overflows in year 2038 on 32-bit architectures. , MinGW - Minimalist GNU for Windows , Newsletters Articles Create Top The timespec_get () function stores the current time, based on the specified time base, in the timespec (3type) structure pointed to by res. int tm_mon Month of year [0,11]. For a class, we had to switch to the c99 compiler instead of gnu but now timespec seems to be broken. h> int clock_getres (clockid_t clk_id, struct timespec *res); int clock_gettime (clockid_t clk_id, struct timespec *tp); int clock_settime (clockid_t clk_id, const struct timespec *tp); Link with -lrt (only for glibc versions before 2. If the tv_nsec field of one of the timespec structures has the special value UTIME_NOW, then the corresponding file timestamp is set to the current time. struct timespec represents a simple calendar time, or an elapsed time, with sub-second resolution. I was also thinking of QueryPerformanceFrequency. Feb 4, 2021 · I have multiple struct timespec values and a time_t value. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up- to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7. The following sketch implements a function suitable for use in a context where the timespec structure is required for a conditional timeout: static void example (struct timespec *spec, time_t minutes) { struct timeval elapsed; (void)gettimeofday (&elapsed, NULL Although the GNU C Library will continue to provide it indefinitely, portable programs should use clock_gettime or timespec_get instead. 48, the stat structure supports nanosecond resolution for the three file timestamp fields. struct timespec Thomas Gschwind (tom@create. h> struct timespec { time_t tv_sec; /* Seconds */ /* */ tv_nsec; /* Nanoseconds [0, 999'999'999] */ }; DESCRIPTION ¶ Describes times in seconds and nanoseconds. h> int sem_timedwait(sem_t *restrict sem, const struct timespec *restrict In particular, all interfaces returning a ‘struct timeval’ or ‘struct timespec’ have been replaced because the tv_sec member overflows in year 2038 on 32-bit architectures. h> header shall declare the structure tm, which shall include at least the following members: int tm_sec Seconds [0,60]. 17, Real-time library (librt, -lrt) SYNOPSIS top #include <time. Jun 20, 2017 · There are multiple ways to get current time – gettimeofday, time, clock_gettime, and some other processor specific implementations. For internal processing, you can use either or both, as is convenient for you. Feature Test Macro Requirements for glibc (see feature It can be stressed that the traditional UNIX timeval and timespec structures represent elapsed time, measured by the system clock. The timespec_getres () function stores the resolution of times retrieved by timespec_get () with the specified time base in the timespec (3type) structure pointed to by tp, if tp is non-NULL. I need to give it the argument of const struct timespec * but start_time is of type struct timespec. This ceiling is an absolute timeout in seconds and nanoseconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC), and it is specified in the following structure: struct timespec { time_t tv_sec; /* seconds */ long tv_nsec; /* nanoseconds */ }; man clock_gettime (2): 関数 clock_getres () は 指定されたクロック clk_id の分解能 (精度) を探し出す。 res が NULL でない場合、その分解能を res で指される struct timespec に格納する。 クロックの分解能は実装に依存し、 特定のプロセスによって設定することはできない。 Time-specification structureSynopsis: #include <time. h>, and the declaration assumed by the pthread library. This makes a difference for the realtime (wall time) clock, which can be reset by the administrator or ntpd, etc. My question is, how does one enable this change to use the 64-bit timespec in the kernel? Its struct timespec allows for higher resolution (ns) timestamps than the timeval of SO_TIMESTAMP (ms). 7k次，点赞7次，收藏75次。本文详细介绍了Linux开发中常用的timespec、timeval、timezone、time_t、time和localtime等结构体，展示了它们的定义、用途和示例。重点讲解了clock_gettime和gettimeofday的使用以及time和localtime的时效性和安全性问题及其解决方案。 Jan 31, 2019 · Table of Contents timespec Refresher Conversion Functions Bonus: timeval conversions Further Reading timespec Refresher As a quick refresher, timespec is a type defined in the ctime header (aka time. 1-2024 The new_value argument is pointer to an itimerspec structure that specifies the new initial value and the new interval for the timer. It can be stressed that the traditional UNIX timeval and timespec structures represent elapsed time, measured by the system clock. If the mutex is already locked, the calling thread shall block until the mutex becomes available as in the pthread_mutex_lock () function. g. fotkdk mlq stsrgnl hmtkqun rmtghk qln rxm qmdqo umlji dmgqo gop ctlrt oirutr mmwva nxujg