browser/external/curl-8.3.0/docs/libcurl/opts/CURLOPT_HEADERDATA.3
2023-09-27 13:43:06 -04:00

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.TH CURLOPT_HEADERDATA 3 "August 22, 2023" "ibcurl 8.3.0" libcurl
.SH NAME
CURLOPT_HEADERDATA \- pointer to pass to header callback
.SH SYNOPSIS
.nf
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HEADERDATA, void *pointer);
.fi
.SH DESCRIPTION
Pass a \fIpointer\fP to be used to write the header part of the received data
to.
If \fICURLOPT_WRITEFUNCTION(3)\fP or \fICURLOPT_HEADERFUNCTION(3)\fP is used,
\fIpointer\fP is passed in to the respective callback.
If neither of those options are set, \fIpointer\fP must be a valid FILE * and
it is used by a plain fwrite() to write headers to.
If you are using libcurl as a win32 DLL, you \fBMUST\fP use a
\fICURLOPT_WRITEFUNCTION(3)\fP or \fICURLOPT_HEADERFUNCTION(3)\fP if you set
this option or you might experience crashes.
.SH DEFAULT
NULL
.SH PROTOCOLS
All
.SH EXAMPLE
.nf
struct my_info {
int shoesize;
char *secret;
};
static size_t header_callback(char *buffer, size_t size,
size_t nitems, void *userdata)
{
struct my_info *i = (struct my_info *)userdata;
/* now this callback can access the my_info struct */
return nitems * size;
}
CURL *curl = curl_easy_init();
if(curl) {
struct my_info my = { 10, "the cookies are in the cupboard" };
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, header_callback);
/* pass in custom data to the callback */
curl_easy_setopt(curl, CURLOPT_HEADERDATA, &my);
curl_easy_perform(curl);
}
.fi
.SH AVAILABILITY
Always
.SH RETURN VALUE
Returns CURLE_OK
.SH "SEE ALSO"
.BR CURLOPT_HEADERFUNCTION "(3), " CURLOPT_WRITEFUNCTION "(3), "