multipart/form-data http post request curl vc++ - visual-c++

Question

first time curl user, working on a curl fileupload with http multipart/form-data request with vc++.
After researching I found two ways to make a multipart/form-data request. Either use "CURLOPT_POSTFIELDS" set a value as an array or use formadd and pass the pointer to CURLOPT_POSTFIELDS. I decided to do the second and configure the different fields of the request with "formdata" (two fields, one file (application/sla) the other one origin (text/plain)
I used wireshark to catch the request and saw that CURL returned CURLE_READ_ERROR (26). Then I added CURLFORM_FILECONTENT, "tmp_3DButton.stl" and got CURL_OK but the server I was sending the request to returned "Bad Media Type" and I saw that CURL didnt send my request as multipart..
(win8 64 bit, visual studio 2015, curl, c++
CURL *curl;
CURLcode res;
char error[CURL_ERROR_SIZE];
struct curl_httppost *formpost = NULL;
struct curl_httppost *lastptr = NULL;
struct curl_slist *headerlist = NULL;
curl_global_init(CURL_GLOBAL_ALL);
// Fill in the file upload field
curl_formadd(&formpost,
&lastptr,
CURLFORM_COPYNAME, "file",
CURLFORM_CONTENTTYPE, "application/sla",
CURLFORM_FILECONTENT, "tmp.stl",
CURLFORM_FILE, filePathSTL,
CURLFORM_END);
// Fill in the filename field
curl_formadd(&formpost,
&lastptr,
CURLFORM_COPYNAME, "origin",
CURLFORM_CONTENTTYPE, "text/plain",
CURLFORM_FILENAME, "se_1_0",
CURLFORM_END);
curl = curl_easy_init();
headerlist = curl_slist_append(headerlist, "Accept: text/plain");
if (curl) {
// URL that receives this POST
curl_easy_setopt(curl, CURLOPT_URL, "http://blabla.com/upload");
//multipart/form-data
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerlist);
curl_easy_setopt(curl, CURLOPT_HTTPPOST, formpost);
2);
curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, error);
error[0] = 0;
// Perform the request, res will get the return code
res = curl_easy_perform(curl);
CString str;
// Check for errors
if (res != CURLE_OK)
{
str.Format("curl_easy_perform return %s [%d]", curl_easy_strerror(res), res);
size_t len = strlen(error);
if (len)
{
_bstr_t bstrt(error);
AfxMessageBox(error);
}
}
curl_easy_cleanup(curl);
filePathSTL is bstrt for example C:\..\..\tmp.stl (with doubled slashes..)

Answer 1

Found an answer, "CURLFORM_FILE" obviously wants a string!