LINUX : Opening and Closing the File.

Program to Open a File and Close it , Along with printing the File Discripter value.

Program will never return the file discripter value as 0,1,or 2 as these values are already reserved for 

0---> Standard Input

1---> Standard Output

2---> Standard Output

Here two system calls are used, read and write, you can get the details of it just by typing man read or man write in the terminal window.

Save the file in .c extension, compile by GCC compiler and execute it.

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/* Program to open the File and Print its file discripter value */
/* User Progam , to be executed in the user space */
/* openfile1.c */

#include<stdio.h>
#include<fcntl.h>

int main()
{
    int fd1,fd2;
    fd1=open("test1.txt",O_CREAT|O_RDWR,0777);
    fd2=open("test2.txt",O_CREAT|O_RDWR,0777);
    if(fd1<0)
    {
        printf("File 1 cannot be open. \n");
    }
    else
    {
        printf("File Discripter value of the File 1 is : %d",fd1);
    }

    if(fd2<0)
    {
        printf("File 2 cannot be open. \n");
    }
    else
    {
        printf("File Discripter value of the File 2 is : %d",fd2);
    }
    return 0;
}