Hello world in C using SGX - c

Question

I noticed some people able to write an SGX code in C code. I tried to do that, Assume I have the following code. Still I don't know how to write a Makefile that can compile these file As I didn't find much information online on how to compile it.
main.c
#define ENCLAVE_FILE "enclave.signed.dll"
#define MAX_BUF_LEN 100
#include "sgx_urts.h"
#include "enclave_u.h"
#include "stdio.h"
#include <string>
int main()
{
//Encalve starts
sgx_enclave_id_t eid;
sgx_status_t ret = SGX_SUCCESS;
sgx_launch_token_t token = { 0 };
int updated = 0;
char buffer[MAX_BUF_LEN] = "Hello world!";
ret = sgx_create_enclave(ENCLAVE_FILE, SGX_DEBUG_FLAG, &token, &updated, &eid, NULL);
if (ret != SGX_SUCCESS) {
printf("\nApp: error %#x, failed to create enclave. \n", ret);
}
//Encalve starts
// (ECALL will happen here).
printf("\nApp: Buffertesrs:\n");
printf("App: Buffer before ECALL: %s\n", buffer);
encalveChangebuffer(eid, buffer, MAX_BUF_LEN);
printf("App: Buffer before ECALL: %s\n", buffer);
}
encalve.c
#include "enclave_t.h"
#include "sgx_trts.h"
#include <stdio.h>
#include <string.h>
void encalveChangebuffer(char * buf, size_t len) {
const char * secret = "Hello from Enclave 2";
if (len > strlen(secret))
memcpy(buf, secret, strlen(secret) + 1);
else
memcpy(buf, "false", strlen("false") + 1);
}
encalve.edl
enclave {
trusted {
/* define ECALLs here. */
public void encalveChangebuffer([in,out,size=len] char * buf, size_t len);
};
untrusted {
/* define OCALLs here. */
};
};
I am looking for a Makefile that can compile sgx c code.

Answer 1

Check out this reference:
SGX Developer Reference.
It has a section about Edger8r Tool that explains how to run that tool to compile enclave.edl to a bunch of C files.
It also has a section about sgx_sign.exe that is needed to produce a signed DLL.
There's a section "Enclave Project Files" that lists all required files and build tool settings.
I don't have all the answers, but that should be a good starting point for building your make file.