| JP Abgrall | 511eca3 | 2014-02-12 13:46:45 -0800 | [diff] [blame] | 1 | .\" @(#) $Header: /tcpdump/master/libpcap/pcap_setnonblock.3pcap,v 1.3 2008-04-06 02:53:22 guy Exp $ |
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| 22 | .TH PCAP_SETNONBLOCK 3PCAP "5 April 2008" |
| 23 | .SH NAME |
| 24 | pcap_setnonblock, pcap_getnonblock \- set or get the state of |
| 25 | non-blocking mode on a capture device |
| 26 | .SH SYNOPSIS |
| 27 | .nf |
| 28 | .ft B |
| 29 | #include <pcap/pcap.h> |
| 30 | .ft |
| 31 | .LP |
| 32 | .nf |
| 33 | .ft B |
| 34 | char errbuf[PCAP_ERRBUF_SIZE]; |
| 35 | .ft |
| 36 | .LP |
| 37 | .ft B |
| 38 | int pcap_setnonblock(pcap_t *p, int nonblock, char *errbuf); |
| 39 | int pcap_getnonblock(pcap_t *p, char *errbuf); |
| 40 | .ft |
| 41 | .fi |
| 42 | .SH DESCRIPTION |
| 43 | .B pcap_setnonblock() |
| 44 | puts a capture handle into ``non-blocking'' mode, or takes it out |
| 45 | of ``non-blocking'' mode, depending on whether the |
| 46 | .I nonblock |
| 47 | argument is non-zero or zero. It has no effect on ``savefiles''. |
| 48 | If there is an error, \-1 is returned and |
| 49 | .I errbuf |
| 50 | is filled in with an appropriate error message; otherwise, 0 is |
| 51 | returned. |
| 52 | In |
| 53 | ``non-blocking'' mode, an attempt to read from the capture descriptor |
| 54 | with |
| 55 | .B pcap_dispatch() |
| 56 | will, if no packets are currently available to be read, return 0 |
| 57 | immediately rather than blocking waiting for packets to arrive. |
| 58 | .B pcap_loop() |
| 59 | and |
| 60 | .B pcap_next() |
| 61 | will not work in ``non-blocking'' mode. |
| 62 | .SH RETURN VALUE |
| 63 | .B pcap_getnonblock() |
| 64 | returns the current ``non-blocking'' state of the capture descriptor; it |
| 65 | always returns 0 on ``savefiles''. |
| 66 | If there is an error, \-1 is returned and |
| 67 | .I errbuf |
| 68 | is filled in with an appropriate error message. |
| 69 | .PP |
| 70 | .I errbuf |
| 71 | is assumed to be able to hold at least |
| 72 | .B PCAP_ERRBUF_SIZE |
| 73 | chars. |
| 74 | .SH SEE ALSO |
| 75 | pcap(3PCAP), pcap_loop(3PCAP), pcap_next_ex(3PCAP), pcap_geterr(3PCAP) |