assert() is defined in assert.h

The program will be terminated

#include <stdio.h>
#include <assert.h>
 
int main()
{
	int a = 10, b = 0;
 
	assert (b != 0);

	printf("End the program ...\n");
 
	return 0;
}
		

exit() is defined in stdlib.h

The program will be terminated

#include <stdio.h>
#include <stdlib.h>
 
int main()
{
	int a = 10, b = 0;

	if(b == 0)
	{
		printf("Divided by zero ...\n");
		exit(EXIT_FAILURE); // -1
	}
 
	printf("End the program ...\n");
 
	return 0;
}
		

errno is a global macro shared by the functions in a program, defined in errno.h

perror(), attach errno message to the parameter string, defined in stdio.h

strerror(), create a string containing the errno message, defined in string.h

Not termnate the program

#include <stdio.h>
#include <errno.h>
#include <string.h>
 
extern int errno;

int main()
{
	FILE *f = fopen("unknown.txt", "r");

	if(f == NULL)
	{
		perror("Errno");
		fprintf(stderr, "Error: %s\n", strerror(errno));
	}
	else
		fclose(f);

	printf("End the program ...\n");
 
	return 0;
}
		

setjmp(buf), initial the buf, return 0

longjmp(buf, value), return an integer value, and jump to the location of setjmp(buf) and re-run setjmp(buf)

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

static jmp_buf buf;

int divide(int a, int b)
{
	if(b == 0)
		longjmp(buf, 1); // throw
	return a/b;
}

int main()
{
	int a = 10;

	for(int b = -5; b <= 5; b++)
	{
		if(!setjmp(buf)) // try
			printf("%d\n", divide(a, b));
		else // catch
			printf("Divided by zero ...\n");
	}

	return 0;
}