test.c

#include <openssl/ssl.h>
#include <openssl/ossl_typ.h>
#include <stdio.h>

int main(){
    SSL_CTX *ctx = NULL;
    ctx = SSL_CTX_new(TLS_method());

    SSL_CTX_set_min_proto_version(ctx, 0);
    SSL_CTX_set_max_proto_version(ctx, 0);

    printf("min ver: %d\n", SSL_CTX_get_min_proto_version(ctx));
    printf("max ver: %d\n", SSL_CTX_get_max_proto_version(ctx));
    return 0;
}