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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
88 lines
1.7 KiB
Markdown
88 lines
1.7 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: CURLOPT_HEADERDATA
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Section: 3
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Source: libcurl
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See-also:
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- CURLOPT_HEADERFUNCTION (3)
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- CURLOPT_WRITEFUNCTION (3)
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- curl_easy_header (3)
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Protocol:
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- All
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---
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# NAME
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CURLOPT_HEADERDATA - pointer to pass to header callback
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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_setopt(CURL *handle, CURLOPT_HEADERDATA, void *pointer);
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~~~
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# DESCRIPTION
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Pass a *pointer* to be used to write the header part of the received data
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to.
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If CURLOPT_WRITEFUNCTION(3) or CURLOPT_HEADERFUNCTION(3) is used,
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*pointer* is passed in to the respective callback.
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If neither of those options are set, *pointer* must be a valid FILE * and
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it is used by a plain fwrite() to write headers to.
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If you are using libcurl as a win32 DLL, you **MUST** use a
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CURLOPT_WRITEFUNCTION(3) or CURLOPT_HEADERFUNCTION(3) if you set
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this option or you might experience crashes.
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# DEFAULT
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NULL
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# EXAMPLE
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~~~c
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struct my_info {
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int shoesize;
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char *secret;
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};
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static size_t header_callback(char *buffer, size_t size,
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size_t nitems, void *userdata)
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{
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struct my_info *i = userdata;
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printf("shoe size: %d\n", i->shoesize);
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/* now this callback can access the my_info struct */
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return nitems * size;
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}
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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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struct my_info my = { 10, "the cookies are in the cupboard" };
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curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, header_callback);
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/* pass in custom data to the callback */
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curl_easy_setopt(curl, CURLOPT_HEADERDATA, &my);
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curl_easy_perform(curl);
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}
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}
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~~~
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# AVAILABILITY
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Always
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# RETURN VALUE
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Returns CURLE_OK
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