我已经为你写了这个例子：

#include <uuid/uuid.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

char *convert_uuid_to_string(uuid_t uuid) {
    char *buf = NULL;
    size_t s = 0;
    FILE *f = open_memstream(&buf, &s);
    for (size_t i = 0; i < 16; ++i) {
        fprintf(f, "%02x", uuid[i]);
    }
    fclose(f);
    return buf;
}

char *generate_v5_uuid(const char *inputStr, const char *namespace) {
    const uuid_t *ns = uuid_get_template(&namespace[1]);
    uuid_t uuid;
    uuid_generate_sha1(uuid, *ns, inputStr, strlen(inputStr));
    return convert_uuid_to_string(uuid);
}

int main() {
    system("set -x ; uuidgen --sha1 -n @url -N string");
    printf("%s\n", generate_v5_uuid("string", "@url"));
}

程序输出：

$ ./a.out 
+ uuidgen --sha1 -n @url -N string
64be9091-88e8-5476-996b-8b541f7bf3e5
64be909188e85476996b8b541f7bf3e5

char *generate_v5_uuid(const char *inputStr, const char *namespace)
{
    uuid_t ns;
    uuid_parse(namespace, ns);
    uuid_t uuid;
    uuid_generate_sha1(uuid, ns, inputStr, strlen(inputStr));
    char str[UUID_STR_LEN];
    uuid_unparse(uuid, str);
    return strdup(str);
}