projects / thirdparty / man-pages.git / blame
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1 | .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
| 2 | .\" | |
| 3 | .\" Permission is granted to make and distribute verbatim copies of this | |
| 4 | .\" manual provided the copyright notice and this permission notice are | |
| 5 | .\" preserved on all copies. | |
| 6 | .\" | |
| 7 | .\" Permission is granted to copy and distribute modified versions of this | |
| 8 | .\" manual under the conditions for verbatim copying, provided that the | |
| 9 | .\" entire resulting derived work is distributed under the terms of a | |
| 10 | .\" permission notice identical to this one. | |
| 11 | .\" | |
| 12 | .\" Since the Linux kernel and libraries are constantly changing, this | |
| 13 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
| 14 | .\" responsibility for errors or omissions, or for damages resulting from | |
| 15 | .\" the use of the information contained herein. The author(s) may not | |
| 16 | .\" have taken the same level of care in the production of this manual, | |
| 17 | .\" which is licensed free of charge, as they might when working | |
| 18 | .\" professionally. | |
| 19 | .\" | |
| 20 | .\" Formatted or processed versions of this manual, if unaccompanied by | |
| 21 | .\" the source, must acknowledge the copyright and authors of this work. | |
| 22 | .\" | |
| 23 | .\" References consulted: | |
| 24 | .\" Linux libc source code | |
| 25 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
| 26 | .\" 386BSD man pages | |
| 27 | .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) | |
| 28 | .\" Modified 2001-04-01 by aeb | |
| 29 | .\" Modified 2003-07-23 by aeb | |
| 30 | .\" | |
| 31 | .TH USLEEP 3 2003-07-23 "" "Linux Programmer's Manual" | |
| 32 | .SH NAME | |
| 33 | usleep \- suspend execution for microsecond intervals | |
| 34 | .SH SYNOPSIS | |
| 35 | .nf | |
| 36 | /* BSD version */ | |
| 37 | .B "#include <unistd.h>" | |
| 38 | .sp | |
| 39 | .BI "void usleep(unsigned long " usec ); | |
| 40 | .sp | |
| 41 | /* SUSv2 version */ | |
| 42 | .B "#define _XOPEN_SOURCE 500" | |
| 43 | .br | |
| 44 | .B "#include <unistd.h>" | |
| 45 | .sp | |
| 46 | .BI "int usleep(useconds_t " usec "); | |
| 47 | .fi | |
| 48 | .SH DESCRIPTION | |
| 63aa9df0 | 49 | The \fBusleep\fP() function suspends execution of the calling process for |
| fea681da MK |
50 | (at least) \fIusec\fP microseconds. The sleep may be lengthened slightly |
| 51 | by any system activity or by the time spent processing the call or by the | |
| 52 | granularity of system timers. | |
| 53 | .SH "RETURN VALUE" | |
| 54 | None (BSD). Or: 0 on success, \-1 on error (SUSv2). | |
| 55 | .SH ERRORS | |
| 56 | .TP | |
| 57 | EINTR | |
| 58 | Interrupted by a signal. | |
| 59 | .TP | |
| 60 | EINVAL | |
| 61 | \fIusec\fP is not smaller than 1000000. | |
| 62 | (On systems where that is considered an error.) | |
| 63 | .SH "CONFORMING TO" | |
| b14d4aa5 | 64 | 4.3BSD. |
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65 | The SUSv2 version returns int, and this is also the prototype |
| 66 | used by glibc 2.2.2. | |
| 67 | Only the EINVAL error return is documented by SUSv2. | |
| 68 | .SH NOTES | |
| 69 | The type | |
| 70 | .B useconds_t | |
| 71 | is an unsigned integer type capable of holding integers | |
| 72 | in the range [0,1000000]. Programs will be more portable | |
| 73 | if they never mention this type explicitly. Use | |
| 74 | .RS | |
| 75 | .nf | |
| 76 | .ta 8 | |
| 77 | .sp | |
| 78 | #include <unistd.h> | |
| 79 | \&... | |
| 80 | unsigned int usecs; | |
| 81 | \&... | |
| 82 | usleep(usecs); | |
| 83 | .sp | |
| 84 | .fi | |
| 85 | .RE | |
| 86 | This type is defined by | |
| 87 | .I <sys/types.h> | |
| 88 | included by | |
| 89 | .I <unistd.h> | |
| 90 | but glibc defines it only when _XOPEN_SOURCE has a value not less than 500, | |
| 91 | or both _XOPEN_SOURCE and _XOPEN_SOURCE_EXTENDED are defined. | |
| 92 | .\" useconds_t also gives problems on HPUX 10. | |
| 93 | .LP | |
| 94 | The interaction of this function with the SIGALRM signal, and with | |
| 95 | other timer functions such as | |
| 96 | .IR alarm (), | |
| 97 | .IR sleep (), | |
| 98 | .IR nanosleep (), | |
| 99 | .IR setitimer (), | |
| 100 | .IR timer_create (), | |
| 101 | .IR timer_delete (), | |
| 102 | .IR timer_getoverrun (), | |
| 103 | .IR timer_gettime (), | |
| 104 | .IR timer_settime (), | |
| 105 | .IR ualarm () | |
| 106 | is unspecified. | |
| 107 | .LP | |
| 108 | This function is obsolete. Use | |
| 109 | .BR nanosleep (2) | |
| 110 | or | |
| 111 | .BR setitimer (2) | |
| 112 | instead. | |
| 113 | .SH "SEE ALSO" | |
| 114 | .BR alarm (2), | |
| 115 | .BR getitimer (2), | |
| 116 | .BR nanosleep (2), | |
| 117 | .BR select (2), | |
| 118 | .BR setitimer (2), | |
| 119 | .BR sleep (3) |