Difference between memcpy() and strncpy() function in C

[Owen Fernandes]

Hello Friend,

I am BSc(IT) student with lots of confusion about the various C functions. I want to be aware about the memcpy() and strncpy() function in C. I don't have any idea about their uses. What is the basic difference between memcpy() and strncpy()?. If you have sound knowledge about the memcpy() and strncpy() function in C then please let me know that. I would greatly appreciate your any help.

[Praetor]

Hi friend,

strcpy() function of C language is meant copy null terminated strings. See following it's details:

• Used to copy each and every byte until it encounters a '#0'.
• This function is not able to determine the data size of copied data.
• This function is not bound with null terminated string.
• This function of C can copy location of memory.

[Katty]

Hi,

The memcpy() function of C programming is used to copy data bytes in memory. But the disadvantage of using memcpy() function is that it doesn't check the 'receiving memory area' overflow. following is the syntax for 'memcpy()' function.
Syntax:

void *memcpy (void *src, void *dest, size_t count);

[kelfro]

strncpy function copies 'n' bytes of data from one data string to another string. This function of C is includes in the 'string.h' library. This C function also copy all the count characters to the particular string of from.suppose there is less number of count characters then the remainder of this is can be padded with character known as '\0'. Please refer following it syntax:

#include <string.h>

char strncpy( const char *from, char *to, size_t count );

[Zecho]

If you want to know about the memcpy() function of C then please study following it's example:

#include<stdio.h>

int main ()

{

char string01 [] = "chain of evidence";

char string02 [80];

memcpy (string02, string01, strlen (string01) 1);

printf ( "string01:% snstring02:% sn", string01 , string02);

memcpy (string01, "", 1);

printf ( "string01:% sn", string01);

return 0 ;

}

[Reegan]

Difference between memcpy() and strncpy() function:

1. strcpy() function of C is related to the copy of null terminated strings.
2. memcpy() function of C is not related to the null terminated strings.
3. strcpy() function can identify the size of data.
4. memcpy() function can not identify the size of data.