I dont understand why I am getting an output like this: StackOver↨< as snprintf should take care of null termination as expected output is StackOver. I am using devcpp IDE.
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main(void)
{
char buffer[10];
printf("%d\n", sizeof(buffer));
snprintf(buffer, sizeof(buffer), "%s", "StackOverflow");
printf("%s", buffer);
return 0;
}
The C Standard states that the copied string shall be nul-terminated:
7.21.6.5 The
snprintffunction...
Description
The
snprintffunction is equivalent tofprintf, except that the output is written into an array (specified by argument s ) rather than to a stream. If n is zero, nothing is written, andsmay be a null pointer. Otherwise, output characters beyond then-1st are discarded rather than being written to the array, and a null character is written at the end of the characters actually written into the array. If copying takes place between objects that overlap, the behavior is undefined.
It appears you are running with an outdated and/or buggy C runtime library as the snprintf() implementation doesn't seem to properly implement the required behavior.
strncpy but with C99 no longer does.
This code is working fine for me. The buffer only has space for 10 characters so sprintf is only able to write the first 9 characters that you tell it to write ("StackOver"). At the tenth character it stores a terminating null character, since every C string must be null-terminated.
The only suggestion I would make is adding a newline when printing the string at the end:
printf("%s\n", buffer);
The lack of a newline at the end might be the reason why your IDE is showing you that ↨ character.
If you want the buffer to fit "StackOverflow" you need to allocate it to something larger.
snprintfprintf("%d\n", sizeof(buffer));intoprintf("%zu\n", sizeof(buffer));since the return type forsizeofissize_t.StackOverwithout a new line. I strongly suspect your C standard library is buggy.