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   usleep    ( 3 )

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Имя (Name)

usleep - suspend execution for microsecond intervals

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Синопсис (Synopsis)

#include <unistd.h>

       int usleep(useconds_t usec);

   Feature Test Macro Requirements for glibc (see
   feature_test_macros(7)):

       usleep():
           Since glibc 2.12:
               (_XOPEN_SOURCE >= 500) && ! (_POSIX_C_SOURCE >= 200809L)
                   || /* Glibc since 2.19: */ _DEFAULT_SOURCE
                   || /* Glibc <= 2.19: */ _BSD_SOURCE
           Before glibc 2.12:
               _BSD_SOURCE || _XOPEN_SOURCE >= 500

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Описание (Description)

The usleep() function suspends execution of the calling thread
       for (at least) usec microseconds.  The sleep may be lengthened
       slightly by any system activity or by the time spent processing
       the call or by the granularity of system timers.

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Возвращаемое значение (Return value)

The usleep() function returns 0 on success.  On error, -1 is
       returned, with errno set to indicate the error.

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Ошибки (Error)

EINTR  Interrupted by a signal; see signal(7).

       EINVAL usec is greater than or equal to 1000000.  (On systems
              where that is considered an error.)

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Атрибуты (Attributes)

For an explanation of the terms used in this section, see
       attributes(7).

       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │Interface                             │ Attribute     │ Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │usleep()                              │ Thread safety │ MT-Safe │
       └──────────────────────────────────────┴───────────────┴─────────┘

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Стандарты (Conforming to)

4.3BSD, POSIX.1-2001.  POSIX.1-2001 declares this function
       obsolete; use nanosleep(2) instead.  POSIX.1-2008 removes the
       specification of usleep().

       On the original BSD implementation, and in glibc before version
       2.2.2, the return type of this function is void.  The POSIX
       version returns int, and this is also the prototype used since
       glibc 2.2.2.

       Only the EINVAL error return is documented by SUSv2 and
       POSIX.1-2001.

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Примечание (Note)

The type useconds_t is an unsigned integer type capable of
       holding integers in the range [0,1000000].  Programs will be more
       portable if they never mention this type explicitly.  Use

           #include <unistd.h>
           ...
               unsigned int usecs;
           ...
               usleep(usecs);

       The interaction of this function with the SIGALRM signal, and
       with other timer functions such as alarm(2), sleep(3),
       nanosleep(2), setitimer(2), timer_create(2), timer_delete(2),
       timer_getoverrun(2), timer_gettime(2), timer_settime(2),
       ualarm(3) is unspecified.

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Смотри также (See also)

alarm(2), getitimer(2), nanosleep(2), select(2), setitimer(2),
       sleep(3), ualarm(3), time(7)

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