CURLOPT_NETRC_FILE man page
CURLOPT_NETRC_FILE — file name to read .netrc info from
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_NETRC_FILE, char *file);
Pass a char * as parameter, pointing to a zero terminated string containing the full path name to the file you want libcurl to use as .netrc file. If this option is omitted, and CURLOPT_NETRC(3) is set, libcurl will attempt to find a .netrc file in the current user's home directory.
The application does not have to keep the string around after setting this option.
Added in 7.10.9
Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or CURLE_OUT_OF_MEMORY if there was insufficient heap space.