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e3fe020089
Remove the PROTOCOLS section from the source files completely and instead generate them based on the header data in the curldown files. It also generates TLS backend information for options marked for TLS as protocol. Closes #13175
98 lines
2.8 KiB
Markdown
98 lines
2.8 KiB
Markdown
---
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c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
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SPDX-License-Identifier: curl
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Title: curl_easy_send
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Section: 3
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Source: libcurl
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See-also:
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- curl_easy_getinfo (3)
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- curl_easy_perform (3)
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- curl_easy_recv (3)
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- curl_easy_setopt (3)
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Protocol:
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- All
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---
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# NAME
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curl_easy_send - sends raw data over an "easy" connection
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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_send(CURL *curl, const void *buffer,
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size_t buflen, size_t *n);
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~~~
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# DESCRIPTION
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This function sends arbitrary data over the established connection. You may
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use it together with curl_easy_recv(3) to implement custom protocols
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using libcurl. This functionality can be particularly useful if you use
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proxies and/or SSL encryption: libcurl takes care of proxy negotiation and
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connection setup.
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**buffer** is a pointer to the data of length **buflen** that you want
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sent. The variable **n** points to receives the number of sent bytes.
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To establish the connection, set CURLOPT_CONNECT_ONLY(3) option before
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calling curl_easy_perform(3) or curl_multi_perform(3). Note that
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curl_easy_send(3) does not work on connections that were created without
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this option.
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The call returns **CURLE_AGAIN** if it is not possible to send data right now
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- the socket is used in non-blocking mode internally. When **CURLE_AGAIN**
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is returned, use your operating system facilities like *select(2)* to wait
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until the socket is writable. The socket may be obtained using
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curl_easy_getinfo(3) with CURLINFO_ACTIVESOCKET(3).
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Furthermore if you wait on the socket and it tells you it is writable,
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curl_easy_send(3) may return **CURLE_AGAIN** if the only data that was sent
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was for internal SSL processing, and no other data could be sent.
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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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CURLcode res;
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curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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/* Do not do the transfer - only connect to host */
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curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 1L);
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res = curl_easy_perform(curl);
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if(res == CURLE_OK) {
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long sockfd;
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size_t sent;
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/* Extract the socket from the curl handle - we need it for waiting. */
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res = curl_easy_getinfo(curl, CURLINFO_ACTIVESOCKET, &sockfd);
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/* send data */
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res = curl_easy_send(curl, "hello", 5, &sent);
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}
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}
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}
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~~~
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# AVAILABILITY
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Added in 7.18.2.
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# RETURN VALUE
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On success, returns **CURLE_OK** and stores the number of bytes actually
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sent into ***n**. Note that this may be less than the amount you wanted to
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send.
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On failure, returns the appropriate error code.
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This function may return **CURLE_AGAIN**. In this case, use your operating
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system facilities to wait until the socket is writable, and retry.
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If there is no socket available to use from the previous transfer, this function
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returns **CURLE_UNSUPPORTED_PROTOCOL**.
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