有没有一种方法可以测试regex_t实例是否成功编译？

int regcomp(regex_t *preg, const char *pattern, int cflags);

#include <stdio.h>
#include <regex.h>

int main() {
    regex_t regex;
    const char *pattern = "abc";
    int ret;

    ret = regcomp(&regex, pattern, 0);
    if (ret == 0) {
        printf("Regex compiled successfully.\n");
        regfree(&regex);
    } else {
        char error_msg[100];
        regerror(ret, &regex, error_msg, sizeof(error_msg));
        printf("Regex compilation failed: %s\n", error_msg);
    }

    return 0;
}