Error handling in C

Error handling:

         Error handling is the process of detecting and responding to errors or exceptional situations that can occur during program execution.

 #include<errno.h>

 Three types of statements we can use in C to handle the error:

1. Strerror(): which returns the pointer to the textual representation of the current error value.
2. Perror(): which is used to display the textual representation.
3. Exit_sucess/Exit_Failure: is to indicate the successful or unsuccessful termination.

Example 01:

// C implementation to see how errno value is

// set in the case of any error in C

#include <stdio.h>

#include <errno.h>

int main()

{

    // If a file is opened which does not exist,

    // then it will be an error and corresponding

    // errno value will be set

    FILE * fp;

    // opening a file which does

    // not exist.

    fp = fopen("GeeksForGeeks.txt", "r");

    printf(" Value of errno: %d\n ", errno);

    return 0;

}

Example 02:

// C implementation to see how perror() and strerror()

// functions are used to print the error messages.

#include <stdio.h>

#include <errno.h>

#include <string.h>

int main ()

{

    FILE *fp;

    // If a file is opened which does not exist,

    // then it will be an error and corresponding

    // errno value will be set

    fp = fopen(" GeeksForGeeks.txt ", "r");

    // opening a file which does

    // not exist.

//  printf("Value of errno: %d\n ", errno);

//  printf("The error message is : %s\n" ,strerror(errno));

    perror("The error is : ");

    return 0;

}

Example 03:

// C implementation which shows the

// use of EXIT_SUCCESS and EXIT_FAILURE.

#include <stdio.h>

#include <errno.h>

#include <string.h>

#include <stdlib.h>

int main ()

{

    FILE * fp;

    fp = fopen ("filedoesnotexist.txt", "rb");

    if (fp == NULL)

    {

        printf("Value of errno: %d\n", errno);

        printf("Error opening the file: %s\n",

                            strerror(errno));

        perror("Error printed by perror");

        exit(EXIT_FAILURE);

        printf("I will not be printed\n");

    }

    else

    {

        fclose (fp);

        exit(EXIT_SUCCESS);

        printf("I will  be printed\n");

    }

    return 0;

}