time_t(3type) — Linux manual page

time_t(3type)                                               time_t(3type)

NAME         top

       time_t, suseconds_t, useconds_t - integer time

LIBRARY         top

       Standard C library (libc)

SYNOPSIS         top

       #include <time.h>

       typedef /* ... */  time_t;

       #include <sys/types.h>

       typedef /* ... */  suseconds_t;
       typedef /* ... */  useconds_t;

DESCRIPTION         top

       time_t Used for time in seconds.  According to POSIX, it is an
              integer type.

       suseconds_t
              Used for time in microseconds.  It is a signed integer type
              capable of storing values at least in the range [-1,
              1000000].

       useconds_t
              Used for time in microseconds.  It is an unsigned integer
              type capable of storing values at least in the range [0,
              1000000].

STANDARDS         top

       time_t C11, POSIX.1-2008.

       suseconds_t
       useconds_t
              POSIX.1-2008.

HISTORY         top

       time_t C89, POSIX.1-2001.

       suseconds_t
       useconds_t
              POSIX.1-2001.

       <sched.h> defines time_t since POSIX.1-2008.

       POSIX.1-2001 defined useconds_t in <unistd.h> too.

NOTES         top

       On some architectures, the width of time_t can be controlled with
       the feature test macro _TIME_BITS.  See feature_test_macros(7).

       The following headers also provide time_t: <sched.h>, <sys/msg.h>,
       <sys/select.h>, <sys/sem.h>, <sys/shm.h>, <sys/stat.h>,
       <sys/time.h>, <sys/types.h>, and <utime.h>.

       The following headers also provide suseconds_t: <sys/select.h> and
       <sys/time.h>.

SEE ALSO         top

       stime(2), time(2), ctime(3), difftime(3), usleep(3),
       timeval(3type)

COLOPHON         top

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Linux man-pages 6.15            2025-05-17                  time_t(3type)

Pages that refer to this page: time(2),  timespec(3type),  timeval(3type),  usleep(3),  feature_test_macros(7)

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