curl :sending mail via SMTP

[phcute]

Greetings!

I was trying to translate an example code snippets from curl 
which demonstrates how to sending an email via smtp using curl 
api.The orignal c code works fine,but my D code failed at the 
beginnig when it is running.

Appreicate for the help to figure me out what's wrong with the 
code.


dmd v2.106.0 , VS community 2019,Win10 64bit
'''
call dmd -m64 curl.lib sendmail.d && sendmail

* No URL set!
curl_easy_perform() failed:URL using bad/illegal format or 
missing URL

'''

D source:

'''
import core.stdc.stdio;
import core.stdc.string;
import core.stdc.stdlib;
import etc.c.curl;
//import std.conv;
//import std.string;

pragma(lib,"curl.lib");


const PASSWORD="real_pass_word";
const FROM_ADDR="sender_email at add.ress";
const TO_ADDR="receiver_email at add.ress";
const CC_ADDR="cc_copy_email at add.ress";

const FROM_MAIL="sender_email at add.ress";
const TO_MAIL="receiver_email at add.ress";
const CC_MAIL="cc_copy_email at add.ress";

const SMTP_VALUE="smtp://smtp-mail.outlook.com:25";//M$ 
outlook.com mail SMTP...


//static const char* payload_text=cast(const char*)(

     enum contents=(
         "To: " ~ TO_MAIL ~ "\r\n" ~
         "From: " ~ FROM_MAIL ~ "\r\n" ~
         "Cc: " ~ CC_MAIL  ~ "\r\n" ~
         "\r\n" ~
         "Subject: SMTP example message" ~ "\r\n" ~
         "\r\n" ~
         "The body of the message starts here." ~ "\r\n" ~
         "\r\n" ~
         "It could be a lot of lines, could be MIME encoded, 
whatever.\r\n\r\nGood Luck!\r\nGood Luck!" ~ "\r\n");
     	

static const char* payload_text= cast(const char*)contents.ptr;

     struct upload_status
     {
     	size_t bytes_read;
     }

     static size_t payload_source(char* ptr,size_t size,size_t 
nmemb,void* userp)
     {
     	upload_status* upload_ctx=cast(upload_status*)userp;
     	//char* data;
     	size_t room=size*nmemb;
     	
     	if((size==0)||(nmemb==0)||((size*nmemb)<1))
     	{
     		return 0;
     	}
     	
     	const char* data=&payload_text[upload_ctx.bytes_read];
     	//const char* data=null;
     
	//memcpy(cast(void*)data,cast(void*)payload_text,upload_ctx.bytes_read);
     	if(data)
     	{
     		size_t len=strlen(data);
     		if(room<len)
     		{
     			len=room;
     		}
     		memcpy(ptr,data,len);
     		upload_ctx.bytes_read+=len;
     		
     		return len;
     	}
     	return 0;
     	
     }
     //extern(C) int main(int argc,char** argv) ---> betterC ? no
     void main()
     {

     	CURL* curl;
     	CURLcode res=CurlError.ok;
     	curl_slist* recipents=null;
     	upload_status upload_ctx={0};
     	
     	curl=curl_easy_init();
     	
     	if(curl)
     	{
     		curl_easy_setopt(curl,CurlProto.smtp,SMTP_VALUE.ptr);
     		
     		curl_easy_setopt(curl,CurlOption.username,FROM_MAIL.ptr);
     		curl_easy_setopt(curl,CurlOption.mail_from,FROM_ADDR.ptr);
     		curl_easy_setopt(curl,CurlOption.password,PASSWORD.ptr);
     		
     		recipents=curl_slist_append(recipents,TO_ADDR.ptr);
     		recipents=curl_slist_append(recipents,CC_ADDR.ptr);
     		curl_easy_setopt(curl,CurlOption.mail_rcpt,recipents);
     		
     
		curl_easy_setopt(curl,CurlOption.readfunction,&payload_source);
     		curl_easy_setopt(curl,CurlOption.readdata,&upload_ctx);
     		curl_easy_setopt(curl,CurlOption.verbose,1);
     		curl_easy_setopt(curl,CurlOption.upload,1);
     		curl_easy_setopt(curl,CurlOption.use_ssl,CurlUseSSL.all);
     		
     		curl_easy_setopt(curl,CurlOption.ssl_verifypeer,0);
     		
     		res=curl_easy_perform(curl);
     		
     		if(res!=CurlError.ok)
     		{
     			fprintf(stderr,"curl_easy_perform() 
failed:%s\n",curl_easy_strerror(res));
     		}
     		
     		curl_slist_free_all(recipents);
     		
     		
     		curl_easy_cleanup(curl);
     	}
     	
     	getchar();
     	
     	//return 0;
     	
     }

'''