CODEWITHSUNDEEP
clinuxlinux-kerneloperating-system
user3532122
user3532122

Reputation: 15

Issue while writting the data using write system call in linux

I've written the example code for read,write system call in linux....Executed without any issues.

As a result,storing the buffer data into a file....

Expected result to be stored in a file is Hello World!..But i'm getting the data in a file like this Hello World!^@

What shall i need to do inorder to get the expected result?

int main(int argc , char *argv[])
{
        int fd;
        char buff[14];
        fd = open("myfile.txt",O_CREAT| O_WRONLY,0777);

        if(fd == -1)
        {
                printf("Failed to open the file to write");
                exit(0);
        }

        write(fd,"Hello World!\n",13);
        close(fd);

        fd = open("myfile.txt",O_RDONLY,0777);

        if(fd == -1)
        {
                printf("Failed to open the file to read");
                exit(0);
        }

        read(fd,buff,14);
        buff[14] = '\0';
        close(fd); 
        printf("Buff is %s\n",buff);

        return 0;
}

Upvotes: 0

Views: 74

Answers (1)

Some programmer dude
Some programmer dude

Reputation: 409196

You declare buff to be 14 characters, but you write the terminator at position 15. That leads to two instances of undefined behavior: One because you write out of bounds of the array, and one because when you print the buffer you have uninitialized data at position 14.

Upvotes: 2

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