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| | 32 | .\" @(#)usleep.3 8.1 (Berkeley) 6/4/93 |
| | 33 | .\" $FreeBSD: src/lib/libc/gen/usleep.3,v 1.18 2002/12/29 00:59:09 mike Exp $ |
| | 34 | .\" |
| | 35 | .Dd February 13, 1998 |
| | 36 | .Dt USLEEP 3 |
| | 37 | .Os |
| | 38 | .Sh NAME |
| | 39 | .Nm usleep |
| | 40 | .Nd suspend process execution for an interval measured in microseconds |
| | 41 | .Sh LIBRARY |
| | 42 | .Lb libc |
| | 43 | .Sh SYNOPSIS |
| | 44 | .In unistd.h |
| | 45 | .Ft int |
| | 46 | .Fn usleep "useconds_t microseconds" |
| | 47 | .Sh DESCRIPTION |
| | 48 | The |
| | 49 | .Fn usleep |
| | 50 | function suspends execution of the calling process until either |
| | 51 | .Fa microseconds |
| | 52 | microseconds have elapsed or a signal is delivered to the process and its |
| | 53 | action is to invoke a signal-catching function or to terminate the |
| | 54 | process. |
| | 55 | System activity may lengthen the sleep by an indeterminate amount. |
| | 56 | .Pp |
| | 57 | This function is implemented using |
| | 58 | .Xr nanosleep 2 |
| | 59 | by pausing for |
| | 60 | .Fa microseconds |
| | 61 | microseconds or until a signal occurs. |
| | 62 | Consequently, in this implementation, |
| | 63 | sleeping has no effect on the state of process timers, |
| | 64 | and there is no special handling for SIGALRM. |
| | 65 | .Sh RETURN VALUES |
| | 66 | .Rv -std usleep |
| | 67 | .Sh ERRORS |
| | 68 | The |
| | 69 | .Fn usleep |
| | 70 | function |
| | 71 | will fail if: |
| | 72 | .Bl -tag -width Er |
| | 73 | .It Bq Er EINTR |
| | 74 | A signal was delivered to the process and its |
| | 75 | action was to invoke a signal-catching function. |
| | 76 | .El |
| | 77 | .Sh SEE ALSO |
| | 78 | .Xr nanosleep 2 , |
| | 79 | .Xr sleep 3 |
| | 80 | .Sh HISTORY |
| | 81 | The |
| | 82 | .Fn usleep |
| | 83 | function appeared in |
| | 84 | .Bx 4.3 . |
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