1curl_easy_nextheader(3) libcurl curl_easy_nextheader(3)
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6 curl_easy_nextheader - get the next HTTP header
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9 #include <curl/curl.h>
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11 struct curl_header *curl_easy_nextheader(CURL *easy,
12 unsigned int origin,
13 int request,
14 struct curl_header *prev);
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17 This function lets an application iterate over all previously received
18 HTTP headers.
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20 The origin argument is for specifying which headers to receive, as a
21 single HTTP transfer might provide headers from several different
22 places and they may then have different importance to the user and
23 headers using the same name might be used. The origin is a bitmask for
24 what header sources you want. See the curl_easy_header(3) man page for
25 the origin descriptions.
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27 The request argument tells libcurl from which request you want headers
28 from. A single transfer might consist of a series of HTTP requests and
29 this argument lets you specify which particular individual request you
30 want the headers from. 0 being the first request and then the number
31 increases for further redirects or when multi-state authentication is
32 used. Passing in -1 is a shortcut to "the last" request in the series,
33 independently of the actual amount of requests used.
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35 It is suggested that you pass in the same origin and request when iter‐
36 ating over a range of headers as changing the value mid-loop might give
37 you unexpected results.
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39 If prev is NULL, this function returns a pointer to the first header
40 stored within the given scope (origin + request).
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42 If prev is a pointer to a previously returned header struct,
43 curl_easy_nextheader(3) returns a pointer the next header stored within
44 the given scope. This way, an application can iterate over all avail‐
45 able headers.
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47 The memory for the struct this points to, is owned and managed by
48 libcurl and is associated with the easy handle. Applications must copy
49 the data if they want it to survive subsequent API calls or the life-
50 time of the easy handle.
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53 struct curl_header *prev = NULL;
54 struct curl_header *h;
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56 /* extract the normal headers from the first request */
57 while((h = curl_easy_nextheader(easy, CURLH_HEADER, 0, prev))) {
58 printf("%s: %s\n", h->name, h->value);
59 prev = h;
60 }
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62 /* extract the normal headers + 1xx + trailers from the last request */
63 unsigned int origin = CURLH_HEADER| CURLH_1XX | CURLH_TRAILER;
64 while((h = curl_easy_nextheader(easy, origin, -1, prev))) {
65 printf("%s: %s\n", h->name, h->value);
66 prev = h;
67 }
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70 Added in 7.83.0. Officially supported since 7.84.0.
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73 This function returns the next header, or NULL when there are no more
74 (matching) headers or an error occurred.
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76 If this function returns NULL when prev was set to NULL, then there are
77 no headers available within the scope to return.
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80 curl_easy_header(3), curl_easy_perform(3)
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84libcurl 8.2.1 July 07, 2023 curl_easy_nextheader(3)