Check if a Windows exe built with Unity.

check_unity.c

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

int check_unity(const char *filename)
{
    FILE *f = fopen(filename, "rb");
    const char *s = "UnityPlayer";
    char buf[20];
    int len = strlen(s);
    int is_unity = 0;

    if (!f)
        return 0;

    fseek(f, 8545324, SEEK_SET);
    fscanf(f, "%15s", buf);

    if (strncmp(s, buf, len) == 0)
        is_unity = 1;

    fclose(f);

    return is_unity;
}

int main(int argc, char *argv[])
{
    if (argc < 2) {
        printf("Usage: %s <filename>\n", argv[0]);
        return 1;
    }

    if (check_unity(argv[1]))
        printf("Unity!\n");
    else
        printf("Not Unity\n");

    return 0;
}