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| 20 | .TH PCAP_INIT 3PCAP "11 April 2020" |
| 21 | .SH NAME |
| 22 | pcap_init \- initialize the library |
| 23 | .SH SYNOPSIS |
| 24 | .nf |
| 25 | .ft B |
| 26 | #include <pcap/pcap.h> |
| 27 | .ft |
| 28 | .LP |
| 29 | .nf |
| 30 | .ft B |
| 31 | char errbuf[PCAP_ERRBUF_SIZE]; |
| 32 | .ft |
| 33 | .LP |
| 34 | .ft B |
| 35 | int pcap_init(unsigned int opts, char *errbuf); |
| 36 | .ft |
| 37 | .fi |
| 38 | .SH DESCRIPTION |
| 39 | .BR pcap_init () |
| 40 | is used to initialize the Packet Capture library. |
| 41 | .I opts |
| 42 | specifies options for the library; |
| 43 | currently, the options are: |
| 44 | .TP |
| 45 | .B PCAP_CHAR_ENC_LOCAL |
| 46 | Treat all strings supplied as arguments, and return all strings to the |
| 47 | caller, as being in the local character encoding. |
| 48 | .TP |
| 49 | .B PCAP_CHAR_ENC_UTF_8 |
| 50 | Treat all strings supplied as arguments, and return all strings to the |
| 51 | caller, as being in UTF-8. |
| 52 | .PP |
| 53 | On UNIX-like systems, the local character encoding is assumed to be |
| 54 | UTF-8, so no character encoding transformations are done. |
| 55 | .PP |
| 56 | On Windows, the local character encoding is the local ANSI code page. |
| 57 | .PP |
| 58 | If |
| 59 | .BR pcap_init () |
| 60 | is not called, strings are treated as being in the local ANSI code page |
| 61 | on Windows, |
| 62 | .BR pcap_lookupdev (3PCAP) |
| 63 | will succeed if there is a device on which to capture, and |
| 64 | .BR pcap_create (3PCAP) |
| 65 | makes an attempt to check whether the string passed as an argument is a |
| 66 | UTF-16LE string - note that this attempt is unsafe, as it may run past |
| 67 | the end of the string - to handle |
| 68 | .BR pcap_lookupdev () |
| 69 | returning a UTF-16LE string. Programs that don't call |
| 70 | .BR pcap_init () |
| 71 | should, on Windows, call |
| 72 | .BR pcap_wsockinit () |
| 73 | to initialize Winsock; this is not necessary if |
| 74 | .BR pcap_init () |
| 75 | is called, as |
| 76 | .BR pcap_init () |
| 77 | will initialize Winsock itself on Windows. |
| 78 | .SH RETURN VALUE |
| 79 | .BR pcap_init () |
| 80 | returns |
| 81 | .B 0 |
| 82 | on success and |
| 83 | .B \-1 |
| 84 | on failure. |
| 85 | If |
| 86 | .B \-1 |
| 87 | is returned, |
| 88 | .I errbuf |
| 89 | is filled in with an appropriate error message. |
| 90 | .I errbuf |
| 91 | is assumed to be able to hold at least |
| 92 | .B PCAP_ERRBUF_SIZE |
| 93 | chars. |
| 94 | .SH BACKWARD COMPATIBILITY |
| 95 | This function became available in libpcap release 1.10.0. In previous |
| 96 | releases, on Windows, all strings supplied as arguments, and all strings |
| 97 | returned to the caller, are in the local character encoding. |
| 98 | .SH SEE ALSO |
| 99 | .BR pcap (3PCAP) |