try_catch_throw.c

#include <stdio.h>
#include <setjmp.h>
#include <string.h>
#include <stdbool.h>

#define NULLSTRING 1
#define EMPTYSTRING 2

jmp_buf buf;
int exception_number;

#define TRY if ((exception_number = setjmp(buf)) == 0)
#define CATCH(x) else if (exception_number == x)
#define CATCHALL else
#define THROW(ex) (longjmp(buf, ex))

_Bool palindrome(const char *str)
{

    if (str == NULL)
        THROW(NULLSTRING);

    size_t len = strlen(str);

    if (len == 0)
        THROW(EMPTYSTRING);

    size_t i;
    for (i = 0; i <= len / 2; i++)
    {

        if (str[i] != str[len - i - 1])
            return false;
    }
    return true;
}

int main()
{

    TRY
    {
        printf("%d", palindrome("saa"));
    }
    CATCH(NULLSTRING)
    {
        printf("%s", "NullString!!!\n");
    }
    CATCH(EMPTYSTRING)
    {
        printf("%s", "EmptyString!!!\n");
    }
    CATCHALL
    {
        printf("%s", "unrecognized exception!\n");
    }

    return 0;
}