DOKK / manpages / debian 12 / libcurl4-doc / CURLOPT_READDATA.3.en
CURLOPT_READDATA(3) curl_easy_setopt options CURLOPT_READDATA(3)

CURLOPT_READDATA - pointer passed to the read callback

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_READDATA, void *pointer);

Data pointer to pass to the file read function. If you use the CURLOPT_READFUNCTION(3) option, this is the pointer you will get as input in the fourth argument to the callback.

If you do not specify a read callback but instead rely on the default internal read function, this data must be a valid readable FILE * (cast to 'void *').

If you are using libcurl as a win32 DLL, you MUST use a CURLOPT_READFUNCTION(3) if you set this option or you will experience crashes.

By default, this is a FILE * to stdin.

This is used for all protocols when sending data.

CURL *curl = curl_easy_init();
struct MyData this;
if(curl) {

curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
/* pass pointer that gets passed in to the
CURLOPT_READFUNCTION callback */
curl_easy_setopt(curl, CURLOPT_READDATA, &this);
curl_easy_perform(curl); }

This option was once known by the older name CURLOPT_INFILE, the name CURLOPT_READDATA(3) was introduced in 7.9.7.

This will return CURLE_OK.

CURLOPT_READFUNCTION(3), CURLOPT_WRITEDATA(3),

January 2, 2023 libcurl 7.88.1