1CURLOPT_HEADER(3) curl_easy_setopt options CURLOPT_HEADER(3)
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6 CURLOPT_HEADER - pass headers to the data stream
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9 #include <curl/curl.h>
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11 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HEADER, long onoff);
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14 Pass the long value onoff set to 1 to ask libcurl to include the head‐
15 ers in the write callback (CURLOPT_WRITEFUNCTION(3)). This option is
16 relevant for protocols that actually have headers or other meta-data
17 (like HTTP and FTP).
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19 When asking to get the headers passed to the same callback as the body,
20 it is not possible to accurately separate them again without detailed
21 knowledge about the protocol in use.
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23 Further: the CURLOPT_WRITEFUNCTION(3) callback is limited to only ever
24 get a maximum of CURL_MAX_WRITE_SIZE bytes passed to it (16KB), while a
25 header can be longer and the CURLOPT_HEADERFUNCTION(3) supports getting
26 called with headers up to CURL_MAX_HTTP_HEADER bytes big (100KB).
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28 It is often better to use CURLOPT_HEADERFUNCTION(3) to get the header
29 data separately.
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31 While named confusingly similar, CURLOPT_HTTPHEADER(3) is used to set
32 custom HTTP headers!
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35 0
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38 Most
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41 CURL *curl = curl_easy_init();
42 if(curl) {
43 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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45 curl_easy_setopt(curl, CURLOPT_HEADER, 1L);
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47 curl_easy_perform(curl);
48 }
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51 Provided in all libcurl versions.
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54 Returns CURLE_OK.
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57 CURLOPT_HEADERFUNCTION(3), CURLOPT_HTTPHEADER(3),
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61libcurl 7.85.0 May 17, 2022 CURLOPT_HEADER(3)