strcpy in c is behaving different

Asked May 16 '18 at 15:22

Active May 16 '18 at 15:40

Viewed 77 times

I am trying to understand strcpy() function but I could not. As said in this page If destination string length is less than source string, entire source string value won’t be copied into destination string, Instead it will be truncated. But when I tried to run this program

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

int main()
{
    char my_full_name[]="TomCruse_MI";
    char my_school_name[]="DON_BOSCO";
    strcpy(my_school_name, my_full_name);
    printf("After strcpy() function to copy my name into my school : \'%s\'\n" , my_school_name);
    printf("\n");
    return 0;
}

I am getting the out as :

After strcpy() function to copy my name into my school : 'TomCruse_MI'

My question is how come the string 'TomCruse_MI' is not getting truncated even though the source string is larger than the destination size.

asked May 16 '18 at 15:22

vicky

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1

undefined behaviour. You broke something but you'll know it later in your program. Or it'll work. – Jean-François Fabre May 16 '18 at 15:24
Behaving different---Undefined behavior – Pushan Gupta May 16 '18 at 15:25
`my_school_nane` is not big enough ! – Stargateur May 16 '18 at 15:25
5

That site you linked is **fundamentally wrong**. There will be no truncation etc. (since the function *cannot* know the destination buffer's size), asking to copy more characters than the buffer can hold is simply Undefined Behaviour (a buffer overrun), plain and simple. – Angew is no longer proud of SO May 16 '18 at 15:29
that site is appalling indeed. Note that the example given uses a _bigger_ destination size so it works... Don't believe everything on the internet. Read StackOverflow :) – Jean-François Fabre May 16 '18 at 15:36
Wow I am also appalled by the site linked. Here is a better link for you to use. http://man7.org/linux/man-pages/man3/strcpy.3.html – iamJP May 16 '18 at 15:40
4

Bah.. another "programming" site for a blacklist... – Eugene Sh. May 16 '18 at 15:53
My goodness, who runs that site? – Christian Gibbons May 16 '18 at 16:02
Some Java enthusiasts? – Jean-François Fabre May 16 '18 at 16:04
note: `TomCruse_MI` should be `TomCruise_MI` (effect of the truncation already?) – Jean-François Fabre May 16 '18 at 16:08

strcpy in c is behaving different

0 Answers0