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

int validate_var(char *str)
{
    regex_t reg;
    printf("error code %d\n" ,regcomp(&reg, "^[a-zA-Z]+[a-zA-Z0-9]*$", 0));
    int r = regexec(&reg, str, 0, NULL, 0);
    regfree(&reg);

    return r;
}

int main() {
    printf("%d\n", validate_var("abc")); // Reports 1, This makes sense
    printf("%d\n", validate_var("17"));  // Reports 1, This doesn't make sense
}