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| .TH CURLOPT_UPKEEP_INTERVAL_MS 3 "November 04, 2020" "libcurl 7.78.0" "curl_easy_setopt options" |
| |
| .SH NAME |
| CURLOPT_UPKEEP_INTERVAL_MS \- connection upkeep interval |
| .SH SYNOPSIS |
| #include <curl/curl.h> |
| |
| CURLcode curl_easy_setopt(CURL *handle, CURLOPT_UPKEEP_INTERVAL_MS, long upkeep_interval_ms); |
| .SH DESCRIPTION |
| Some protocols have "connection upkeep" mechanisms. These mechanisms usually |
| send some traffic on existing connections in order to keep them alive; this |
| can prevent connections from being closed due to overzealous firewalls, for |
| example. |
| |
| The user needs to explicitly call \fIcurl_easy_upkeep(3)\fP in order to |
| perform the upkeep work. |
| |
| Currently the only protocol with a connection upkeep mechanism is HTTP/2: when |
| the connection upkeep interval is exceeded and \fIcurl_easy_upkeep(3)\fP |
| is called, an HTTP/2 PING frame is sent on the connection. |
| |
| .SH DEFAULT |
| CURL_UPKEEP_INTERVAL_DEFAULT (currently defined as 60000L, which is 60 seconds) |
| .SH EXAMPLE |
| .nf |
| CURL *curl = curl_easy_init(); |
| if(curl) { |
| /* Make a connection to an HTTP/2 server. */ |
| curl_easy_setopt(curl, CURLOPT_URL, "https://example.com"); |
| |
| /* Set the interval to 30000ms / 30s */ |
| curl_easy_setopt(curl, CURLOPT_UPKEEP_INTERVAL_MS, 30000L); |
| |
| curl_easy_perform(curl); |
| |
| /* Perform more work here. */ |
| |
| /* While the connection is being held open, curl_easy_upkeep() can be |
| called. If curl_easy_upkeep() is called and the time since the last |
| upkeep exceeds the interval, then an HTTP/2 PING is sent. */ |
| curl_easy_upkeep(curl); |
| |
| /* Perform more work here. */ |
| |
| /* always cleanup */ |
| curl_easy_cleanup(curl); |
| } |
| .fi |
| .SH AVAILABILITY |
| Added in 7.62.0 |
| .SH RETURN VALUE |
| Returns CURLE_OK |
