Annotation of embedaddon/curl/docs/libcurl/opts/CURLOPT_INTERLEAVEFUNCTION.3, revision 1.1.1.1
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23: .TH CURLOPT_INTERLEAVEFUNCTION 3 "March 23, 2020" "libcurl 7.70.0" "curl_easy_setopt options"
24:
25: .SH NAME
26: CURLOPT_INTERLEAVEFUNCTION \- callback function for RTSP interleaved data
27: .SH SYNOPSIS
28: .nf
29: #include <curl/curl.h>
30:
31: size_t interleave_callback(void *ptr, size_t size, size_t nmemb,
32: void *userdata);
33:
34: CURLcode curl_easy_setopt(CURL *handle, CURLOPT_INTERLEAVEFUNCTION,
35: interleave_callback);
36: .SH DESCRIPTION
37: Pass a pointer to your callback function, which should match the prototype
38: shown above.
39:
40: This callback function gets called by libcurl as soon as it has received
41: interleaved RTP data. This function gets called for each $ block and therefore
42: contains exactly one upper-layer protocol unit (e.g. one RTP packet). Curl
43: writes the interleaved header as well as the included data for each call. The
44: first byte is always an ASCII dollar sign. The dollar sign is followed by a
45: one byte channel identifier and then a 2 byte integer length in network byte
46: order. See \fIRFC2326 Section 10.12\fP for more information on how RTP
47: interleaving behaves. If unset or set to NULL, curl will use the default write
48: function.
49:
50: Interleaved RTP poses some challenges for the client application. Since the
51: stream data is sharing the RTSP control connection, it is critical to service
52: the RTP in a timely fashion. If the RTP data is not handled quickly,
53: subsequent response processing may become unreasonably delayed and the
54: connection may close. The application may use \fICURL_RTSPREQ_RECEIVE\fP to
55: service RTP data when no requests are desired. If the application makes a
56: request, (e.g. \fICURL_RTSPREQ_PAUSE\fP) then the response handler will
57: process any pending RTP data before marking the request as finished.
58:
59: The \fICURLOPT_INTERLEAVEDATA(3)\fP is passed in the \fIuserdata\fP argument in
60: the callback.
61: .SH DEFAULT
62: NULL, the interleave data is then passed to the regular write function:
63: \fICURLOPT_WRITEFUNCTION(3)\fP.
64: .SH PROTOCOLS
65: RTSP
66: .SH EXAMPLE
67: .nf
68: static size_t rtp_write(void *ptr, size_t size, size_t nmemb, void *user)
69: {
70: struct local *l = (struct local *)user;
71: /* take care of the packet in 'ptr', then return... */
72: return size * nmemb;
73: }
74: {
75: struct local rtp_data;
76: curl_easy_setopt(curl, CURLOPT_INTERLEAVEFUNCTION, rtp_write);
77: curl_easy_setopt(curl, CURLOPT_INTERLEAVEDATA, &rtp_data);
78: }
79: .fi
80: .SH AVAILABILITY
81: Added in 7.20.0
82: .SH RETURN VALUE
83: Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
84: .SH "SEE ALSO"
85: .BR CURLOPT_INTERLEAVEDATA "(3), " CURLOPT_RTSP_REQUEST "(3), "
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