CURLOPT_HEADERDATA(3)

1CURLOPT_HEADERDATA(3)               libcurl              CURLOPT_HEADERDATA(3)
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NAME

6       CURLOPT_HEADERDATA - pointer to pass to header callback
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SYNOPSIS

9       #include <curl/curl.h>
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11       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HEADERDATA, void *pointer);
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DESCRIPTION

14       Pass a pointer to be used to write the header part of the received data
15       to.
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17       If  CURLOPT_WRITEFUNCTION(3)  or  CURLOPT_HEADERFUNCTION(3)  is   used,
18       pointer will be passed in to the respective callback.
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20       If neither of those options are set, pointer must be a valid FILE * and
21       it will be used by a plain fwrite() to write headers to.
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23       If you are using libcurl as a win32 DLL, you MUST use a  CURLOPT_WRITE‐
24       FUNCTION(3)  or CURLOPT_HEADERFUNCTION(3) if you set this option or you
25       will experience crashes.
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DEFAULT

28       NULL
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PROTOCOLS

31       All
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EXAMPLE

34       struct my_info {
35         int shoesize;
36         char *secret;
37       };
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39       static size_t header_callback(char *buffer, size_t size,
40                                     size_t nitems, void *userdata)
41       {
42         struct my_info *i = (struct my_info *)userdata;
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44         /* now this callback can access the my_info struct */
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46         return nitems * size;
47       }
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49       CURL *curl = curl_easy_init();
50       if(curl) {
51         struct my_info my = { 10, "the cookies are in the cupboard" };
52         curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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54         curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, header_callback);
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56         /* pass in custom data to the callback */
57         curl_easy_setopt(curl, CURLOPT_HEADERDATA, &my);
58
59         curl_easy_perform(curl);
60       }
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AVAILABILITY

63       Always
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RETURN VALUE

66       Returns CURLE_OK
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