Question

What are the possible ways of handling exceptions in C?

Answer 1

for example, using setjmp.h

Answer 2

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

void first(void);
void second(void);

/* This program's output is:

calling first
calling second
entering second
second failed with type 3 exception; remapping to type 1.
first failed, exception type 1

*/

/* Use a file scoped static variable for the exception stack so we can access
* it anywhere within this translation unit. */
static jmp_buf exception_env;
static int exception_type;

int main() {
void *volatile mem_buffer;

mem_buffer = NULL;
if (setjmp(exception_env)) {
/* if we get here there was an exception */
printf("first failed, exception type %d\n", exception_type);
} else {
/* Run code that may signal failure via longjmp. */
printf("calling first\n");
first();
mem_buffer = malloc(300); /* allocate a resource */
printf(strcpy((char*) mem_buffer, "first succeeded!")); /* ... this will not happen */
}
if (mem_buffer)
free((void*) mem_buffer); /* carefully deallocate resource */
return 0;
}

void first(void) {
jmp_buf my_env;

printf("calling second\n");
memcpy(my_env, exception_env, sizeof(jmp_buf));
switch (setjmp(exception_env)) {
case 3:
/* if we get here there was an exception. */
printf("second failed with type 3 exception; remapping to type 1.\n");
exception_type = 1;

default: /* fall through */
memcpy(exception_env, my_env, sizeof(jmp_buf)); /* restore exception stack */
longjmp(exception_env, exception_type); /* continue handling the exception */

case 0:
/* normal, desired operation */
second();
printf("second succeeded\n"); /* not reached */
}
memcpy(exception_env, my_env, sizeof(jmp_buf)); /* restore exception stack */
}

void second(void) {
printf("entering second\n" ); /* reached */
exception_type = 3;
longjmp(exception_env, exception_type); /* declare that the program has failed */
printf("leaving second\n"); /* not reached */
}

Answer 3

not maths :P

Answer 4

Ahh his is computer stuff sorry cant help ya out there /:

Answer 5

@Tomas
Please help me; you're a software engineer, after all :(

Answer 6

we didn't learn C :P

Answer 7

and you still haven't told me what you "study" :D