Here is C code:

#include <openssl/sha.h>
#include <stdio.h>
char *hash_sha512(char *data){
    SHA512_CTX ctx;
    char *md=malloc(sizeof(char)*(SHA512_DIGEST_LENGTH+1));

    SHA512_Init(&ctx);
    SHA512_Update(&ctx, data, strlen(data));
    SHA512_Final(md, &ctx);
    md[SHA512_DIGEST_LENGTH]='\0';

    return md;
}
int main(int argc, char *argv[]){
    str=hash_sha512("GFLOuJnR19881218");
    printf("%s\n", str);
    free(str);
    return 1;
}

The output:

?<?4????IIA[r?? ?#? 6p?8jD????J?b9?????^X?

Here is PHP code:

$hash=hash('sha512', 'GFLOuJnR19881218', TRUE);

The output:

?<??>4??j??II?-A[r???? ??#??D6p?8jD???????J?b9?????^X?

The results of C code and PHP code are different, what is wrong with my code?