runtime/example/host/src/trampoline.c

#include <string.h>
#include <stdio.h>
#include <unistd.h>

#include <trampoline/types.h>

// writer: Function That Can Write To Guest Memory
// id: Command ID
// args: Pointer To Command Arguments
// Return Value: Returned To The Guest (Unless Early Return Is Enabled)
uint32_t trampoline(trampoline_writer_t writer, uint32_t id, const unsigned char *args) {
    if (id == 100 /* Defined In ../../guest/src/example.c */) {
        // Early Return Allowed
        fprintf(stderr, "Early Return Call Started\n");
        sleep(1);
        fprintf(stderr, "Early Return Call Done\n");
        return 0;
    } else {
        // Normal Call
        const char *str = (const char *) args;
        fprintf(stderr, "Host Has Received: %u: %s\n", id, str);
        return strlen(str) * 2;
    }
}