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                     22: .TH curl_multi_wait 3 "November 28, 2019" "libcurl 7.70.0" "libcurl Manual"
                     23: 
                     24: .SH NAME
                     25: curl_multi_wait - polls on all easy handles in a multi handle
                     26: .SH SYNOPSIS
                     27: .nf
                     28: #include <curl/curl.h>
                     29: 
                     30: CURLMcode curl_multi_wait(CURLM *multi_handle,
                     31:                           struct curl_waitfd extra_fds[],
                     32:                           unsigned int extra_nfds,
                     33:                           int timeout_ms,
                     34:                           int *numfds);
                     35: .ad
                     36: .SH DESCRIPTION
                     37: \fIcurl_multi_wait(3)\fP polls all file descriptors used by the curl easy
                     38: handles contained in the given multi handle set.  It will block until activity
                     39: is detected on at least one of the handles or \fItimeout_ms\fP has passed.
                     40: Alternatively, if the multi handle has a pending internal timeout that has a
                     41: shorter expiry time than \fItimeout_ms\fP, that shorter time will be used
                     42: instead to make sure timeout accuracy is reasonably kept.
                     43: 
                     44: The calling application may pass additional curl_waitfd structures which are
                     45: similar to \fIpoll(2)\fP's pollfd structure to be waited on in the same call.
                     46: 
                     47: On completion, if \fInumfds\fP is non-NULL, it will be populated with the
                     48: total number of file descriptors on which interesting events occurred. This
                     49: number can include both libcurl internal descriptors as well as descriptors
                     50: provided in \fIextra_fds\fP.
                     51: 
                     52: If no extra file descriptors are provided and libcurl has no file descriptor
                     53: to offer to wait for, this function will return immediately. (Try
                     54: \fIcurl_multi_poll(3)\fP instead if you rather avoid this behavior.)
                     55: 
                     56: This function is encouraged to be used instead of select(3) when using the
                     57: multi interface to allow applications to easier circumvent the common problem
                     58: with 1024 maximum file descriptors.
                     59: .SH curl_waitfd
                     60: .nf
                     61: struct curl_waitfd {
                     62:   curl_socket_t fd;
                     63:   short events;
                     64:   short revents;
                     65: };
                     66: .fi
                     67: .IP CURL_WAIT_POLLIN
                     68: Bit flag to curl_waitfd.events indicating the socket should poll on read
                     69: events such as new data received.
                     70: .IP CURL_WAIT_POLLPRI
                     71: Bit flag to curl_waitfd.events indicating the socket should poll on high
                     72: priority read events such as out of band data.
                     73: .IP CURL_WAIT_POLLOUT
                     74: Bit flag to curl_waitfd.events indicating the socket should poll on write
                     75: events such as the socket being clear to write without blocking.
                     76: .SH EXAMPLE
                     77: .nf
                     78: CURL *easy_handle;
                     79: CURLM *multi_handle;
                     80: 
                     81: /* add the individual easy handle */
                     82: curl_multi_add_handle(multi_handle, easy_handle);
                     83: 
                     84: do {
                     85:   CURLMcode mc;
                     86:   int numfds;
                     87: 
                     88:   mc = curl_multi_perform(multi_handle, &still_running);
                     89: 
                     90:   if(mc == CURLM_OK ) {
                     91:     /* wait for activity, timeout or "nothing" */
                     92:     mc = curl_multi_wait(multi_handle, NULL, 0, 1000, &numfds);
                     93:   }
                     94: 
                     95:   if(mc != CURLM_OK) {
                     96:     fprintf(stderr, "curl_multi failed, code %d.\\n", mc);
                     97:     break;
                     98:   }
                     99: 
                    100:   /* 'numfds' being zero means either a timeout or no file descriptors to
                    101:      wait for. Try timeout on first occurrence, then assume no file
                    102:      descriptors and no file descriptors to wait for means wait for 100
                    103:      milliseconds. */
                    104: 
                    105:   if(!numfds) {
                    106:     repeats++; /* count number of repeated zero numfds */
                    107:     if(repeats > 1) {
                    108:       WAITMS(100); /* sleep 100 milliseconds */
                    109:     }
                    110:   }
                    111:   else
                    112:     repeats = 0;
                    113: 
                    114: } while(still_running);
                    115: 
                    116: curl_multi_remove_handle(multi_handle, easy_handle);
                    117: .fi
                    118: .SH RETURN VALUE
                    119: CURLMcode type, general libcurl multi interface error code. See
                    120: \fIlibcurl-errors(3)\fP
                    121: .SH AVAILABILITY
                    122: This function was added in libcurl 7.28.0.
                    123: .SH "SEE ALSO"
                    124: .BR curl_multi_fdset "(3), " curl_multi_perform "(3)", curl_multi_poll "(3) ",