read() return extra characters from file

Question

I am trying to read text from file to print.. While trying if I give the char buffer size it returns some extra character ..

#include 
#include &         


        

Answer 1

This happens because, read() does not null-terminate the output. You need to null-terminate the destination buffer before using it as a string.

Basically passing a non-null terminated char array to printf() as the argument to %s creates undefined behavior as there can be out of bound memory access.

One way of achieving this is to 0-initialize the destination. That way, it will be considered null-terminated after the valid values read and stored by read(). Something like

  char cbuffer[100] = {0};

can help.

That said, change

 printf("%s",&cbuffer);

to

printf("%s",cbuffer);

as %s expects a pointer to a null-terminated array of chars. When you pass the array name to a function, it decays to the pointer to the first element, so you should be ok.