.\" generated by cd2nroff 0.1 from CURLMOPT_SOCKETDATA.md .TH CURLMOPT_SOCKETDATA 3 "March 22 2024" libcurl .SH NAME CURLMOPT_SOCKETDATA \- custom pointer passed to the socket callback .SH SYNOPSIS .nf #include CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_SOCKETDATA, void *pointer); .fi .SH DESCRIPTION A data \fIpointer\fP to pass to the socket callback set with the \fICURLMOPT_SOCKETFUNCTION(3)\fP option. This pointer is not touched by libcurl but is only passed in as the socket callbacks\(aqs \fBclientp\fP argument. .SH DEFAULT NULL .SH PROTOCOLS All .SH EXAMPLE .nf struct priv { void *ours; }; static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp) { struct priv *p = sockp; printf("my ptr: %p\\n", p->ours); if(what == CURL_POLL_REMOVE) { /* remove the socket from our collection */ } if(what & CURL_POLL_IN) { /* wait for read on this socket */ } if(what & CURL_POLL_OUT) { /* wait for write on this socket */ } return 0; } int main(void) { struct priv setup; CURLM *multi = curl_multi_init(); /* ... use socket callback and custom pointer */ curl_multi_setopt(multi, CURLMOPT_SOCKETFUNCTION, sock_cb); curl_multi_setopt(multi, CURLMOPT_SOCKETDATA, &setup); } .fi .SH AVAILABILITY Added in 7.15.4 .SH RETURN VALUE Returns CURLM_OK. .SH SEE ALSO .BR CURLMOPT_SOCKETFUNCTION (3), .BR CURLMOPT_TIMERFUNCTION (3), .BR curl_multi_socket_action (3)