Annotation of embedaddon/curl/docs/libcurl/opts/CURLMOPT_SOCKETFUNCTION.3, revision 1.1
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! 23: .TH CURLMOPT_SOCKETFUNCTION 3 "June 24, 2019" "libcurl 7.70.0" "curl_multi_setopt options"
! 24:
! 25: .SH NAME
! 26: CURLMOPT_SOCKETFUNCTION \- callback informed about what to wait for
! 27: .SH SYNOPSIS
! 28: .nf
! 29: #include <curl/curl.h>
! 30:
! 31: int socket_callback(CURL *easy, /* easy handle */
! 32: curl_socket_t s, /* socket */
! 33: int what, /* describes the socket */
! 34: void *userp, /* private callback pointer */
! 35: void *socketp); /* private socket pointer */
! 36:
! 37: CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_SOCKETFUNCTION, socket_callback);
! 38: .SH DESCRIPTION
! 39: Pass a pointer to your callback function, which should match the prototype
! 40: shown above.
! 41:
! 42: When the \fIcurl_multi_socket_action(3)\fP function is called, it informs the
! 43: application about updates in the socket (file descriptor) status by doing
! 44: none, one, or multiple calls to the \fBsocket_callback\fP. The callback
! 45: function gets status updates with changes since the previous time the callback
! 46: was called. If the given callback pointer is set to NULL, no callback will be
! 47: called.
! 48: .SH "CALLBACK ARGUMENTS"
! 49: \fIeasy\fP identifies the specific transfer for which this update is related.
! 50:
! 51: \fIs\fP is the specific socket this function invocation concerns. If the
! 52: \fBwhat\fP argument is not CURL_POLL_REMOVE then it holds information about
! 53: what activity on this socket the application is supposed to
! 54: monitor. Subsequent calls to this callback might update the \fBwhat\fP bits
! 55: for a socket that is already monitored.
! 56:
! 57: \fBuserp\fP is set with \fICURLMOPT_SOCKETDATA(3)\fP.
! 58:
! 59: \fBsocketp\fP is set with \fIcurl_multi_assign(3)\fP or will be NULL.
! 60:
! 61: The \fBwhat\fP parameter informs the callback on the status of the given
! 62: socket. It can hold one of these values:
! 63: .IP CURL_POLL_IN
! 64: Wait for incoming data. For the socket to become readable.
! 65: .IP CURL_POLL_OUT
! 66: Wait for outgoing data. For the socket to become writable.
! 67: .IP CURL_POLL_INOUT
! 68: Wait for incoming and outgoing data. For the socket to become readable or
! 69: writable.
! 70: .IP CURL_POLL_REMOVE
! 71: The specified socket/file descriptor is no longer used by libcurl.
! 72: .SH DEFAULT
! 73: NULL (no callback)
! 74: .SH PROTOCOLS
! 75: All
! 76: .SH EXAMPLE
! 77: .nf
! 78: static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
! 79: {
! 80: GlobalInfo *g = (GlobalInfo*) cbp;
! 81: SockInfo *fdp = (SockInfo*) sockp;
! 82:
! 83: if(what == CURL_POLL_REMOVE) {
! 84: remsock(fdp);
! 85: }
! 86: else {
! 87: if(!fdp) {
! 88: addsock(s, e, what, g);
! 89: }
! 90: else {
! 91: setsock(fdp, s, e, what, g);
! 92: }
! 93: }
! 94: return 0;
! 95: }
! 96:
! 97: main()
! 98: {
! 99: GlobalInfo setup;
! 100: /* ... use socket callback and custom pointer */
! 101: curl_multi_setopt(multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
! 102: curl_multi_setopt(multi, CURLMOPT_SOCKETDATA, &setup);
! 103: }
! 104: .fi
! 105: .SH AVAILABILITY
! 106: Added in 7.15.4
! 107: .SH RETURN VALUE
! 108: Returns CURLM_OK.
! 109: .SH "SEE ALSO"
! 110: .BR CURLMOPT_SOCKETDATA "(3), " curl_multi_socket_action "(3), "
! 111: .BR CURLMOPT_TIMERFUNCTION "(3) "
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