C library - abort() function

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The C stdlib library abort() function allows us to terminate or exit from the program by raising the 'SIGABRT' signal.

The 'SIGABRT' signal is one of the signals used in operating systems to indicate an abnormal termination of a program.

This function is useful to find the critical error, debugging, or fallback safety.

Syntax

Following is the C library syntax of the abort() function −

void abort(void)

Parameters

This function does not accepts any parameters.

Return Value

This function does not returns any values.

Example 1

In this example, we create a basic c program to demonstrate the use of abort() function.

#include <stdio.h>
#include <stdlib.h> 
int main(void)
{
   FILE *stream;   
   if ((stream = fopen("D:tpwork/tutorialspoint", "r")) == NULL)
   {
      perror("Could not open data file");
      abort();
   }
   return 0;
}

Output

Following is the output −

Could not open data file: No such file or directory

Example 2

Let's create another, we use the abort() function when the allocated memory is 'NULL'. Otherwise prints value of the ptr.

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

int main() {
	int *ptr;
	ptr = (int*)malloc(sizeof(int));
    if (ptr == NULL) {
        printf("Memory allocation failed. Aborting program.\n");
        abort();
    }

    // If allocation was successful, use the allocated memory
    *ptr = 5;
    printf("Value at ptr: %d\n", *ptr);

    // Free the allocated memory
    free(ptr);
    return 0;
}

Output

Following is the output −

Value at ptr: 5

Example 3

Here, we create a C program that opens a file. If the file is not available, we immediately abort the program.

#include <stdio.h>
#include <stdlib.h>
int main () {    
   printf("Opening the tutorialspoint.txt\n");
   FILE *fp;
   
   // open the file   
   fp = fopen("tutorialspoint.txt", "r");

   if (fp == NULL) {
      perror("Aborting the program");
      abort();
   } else {
      printf("File opened successfully\n");
   }
   
   printf("Close tutorialspoint.txt\n");
   
   // close the file
   fclose(fp);
   
   return(0);
}

Output

Following is the output −

Opening the tutorialspoint.txt
Aborting the program: No such file or directory
Aborted (core dumped)