TIMERADD(3)

💖 NAME 💖

timeradd, timersub, timerclear, timerisset, timercmp, timespecadd, timespecsub, timespecclear, timespecisset, timespeccmp — operations on timevals and timespecs

okay bestie, welcome to TIMERADD(3) from the Library Functions Manual 💅✨

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✨ SYNOPSIS ✨

#include <sys/time.h>

void
timeradd(struct timeval *a, struct timeval *b, struct timeval *res);

void
timersub(struct timeval *a, struct timeval *b, struct timeval *res);

void
timerclear(struct timeval *tvp);

int
timerisset(struct timeval *tvp);

int
timercmp(struct timeval *a, struct timeval *b, CMP);

void
timespecadd(struct timespec *a, struct timespec *b,
    struct timespec *res);

void
timespecsub(struct timespec *a, struct timespec *b,
    struct timespec *res);

void
timespecclear(struct timespec *ts);

int
timespecisset(struct timespec *ts);

int
timespeccmp(struct timespec *a, struct timespec *b, CMP);

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🦋 DESCRIPTION 🦋

okay so these macros are literally here to help you manipulate timeval and timespec structures — the ones you use with the clock_gettime(2), clock_settime(2), gettimeofday(2), and settimeofday(2) calls. no cap, they're little time-math besties 🫶

The timeval structure is defined in <sys/time.h> as:

struct timeval {
        long    tv_sec;         /* seconds since Jan. 1, 1970 */
        long    tv_usec;        /* and microseconds */
};

And the timespec structure is defined in <time.h> as:

struct timespec {
        time_t tv_sec;          /* seconds */
        long   tv_nsec;         /* and nanoseconds */
};

• timeradd() and timespecadd() — these add the time information stored in a to b, then store the result in res ✨. The results are simplified so that the value of res->tv_usec or res->tv_nsec is always less than 1 second. periodt.
• timersub() and timespecsub() — these subtract the time information stored in b from a, then store the result in res 💖.
• timerclear() and timespecclear() — these initialize their argument to midnight (0 hour) January 1st, 1970 (the Epoch) 🕛.
• timerisset() and timespecisset() — these return true if their argument is set to any time value other than the Epoch 👀.
• timercmp() and timespeccmp() — these compare a to b using the comparison operator given in CMP, and return the result of that comparison 💅.

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🌈 SEE ALSO 🌈

go peek at clock_gettime(2) and gettimeofday(2) — linked-up besties, iykyk 🧚

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👑 HISTORY 👑

The timeradd() family of macros were imported from NetBSD 1.1, and appeared in FreeBSD 2.2.6. The timespecadd() family of macros were imported from NetBSD 1.3 into FreeBSD 3.0, though they were not exposed to userland until FreeBSD 12.0. iconic timeline behavior, honestly 💜

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xoxo, your Debian manual girlie — this page's source/version is Debian, dated July 30, 2018, and it's TIMERADD(3) through and through 🎀🫶