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curldown is this new file format for libcurl man pages. It is markdown inspired with differences: - Each file has a set of leading headers with meta-data - Supports a small subset of markdown - Uses .md file extensions for editors/IDE/GitHub to treat them nicely - Generates man pages very similar to the previous ones - Generates man pages that still convert nicely to HTML on the website - Detects and highlights mentions of curl symbols automatically (when their man page section is specified) tools: - cd2nroff: converts from curldown to nroff man page - nroff2cd: convert an (old) nroff man page to curldown - cdall: convert many nroff pages to curldown versions - cd2cd: verifies and updates a curldown to latest curldown This setup generates .3 versions of all the curldown versions at build time. CI: Since the documentation is now technically markdown in the eyes of many things, the CI runs many more tests and checks on this documentation, including proselint, link checkers and tests that make sure we capitalize the first letter after a period... Closes #12730
78 lines
1.8 KiB
Markdown
78 lines
1.8 KiB
Markdown
---
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c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
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SPDX-License-Identifier: curl
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Title: curl_easy_upkeep
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Section: 3
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Source: libcurl
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See-also:
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- CURLOPT_TCP_KEEPALIVE (3)
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- CURLOPT_TCP_KEEPIDLE (3)
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---
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# NAME
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curl_easy_upkeep - Perform any connection upkeep checks.
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# SYNOPSIS
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~~~c
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#include <curl/curl.h>
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CURLcode curl_easy_upkeep(CURL *handle);
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~~~
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# DESCRIPTION
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Some protocols have "connection upkeep" mechanisms. These mechanisms usually
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send some traffic on existing connections in order to keep them alive; this
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can prevent connections from being closed due to overzealous firewalls, for
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example.
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Currently the only protocol with a connection upkeep mechanism is HTTP/2: when
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the connection upkeep interval is exceeded and curl_easy_upkeep(3)
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is called, an HTTP/2 PING frame is sent on the connection.
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This function must be explicitly called in order to perform the upkeep work.
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The connection upkeep interval is set with
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CURLOPT_UPKEEP_INTERVAL_MS(3).
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# EXAMPLE
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~~~c
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int main(void)
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{
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CURL *curl = curl_easy_init();
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if(curl) {
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/* Make a connection to an HTTP/2 server. */
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curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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/* Set the interval to 30000ms / 30s */
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curl_easy_setopt(curl, CURLOPT_UPKEEP_INTERVAL_MS, 30000L);
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curl_easy_perform(curl);
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/* Perform more work here. */
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/* While the connection is being held open, curl_easy_upkeep() can be
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called. If curl_easy_upkeep() is called and the time since the last
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upkeep exceeds the interval, then an HTTP/2 PING is sent. */
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curl_easy_upkeep(curl);
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/* Perform more work here. */
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/* always cleanup */
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curl_easy_cleanup(curl);
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}
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}
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~~~
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# AVAILABILITY
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Added in 7.62.0.
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# RETURN VALUE
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On success, returns **CURLE_OK**.
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On failure, returns the appropriate error code.
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