'strncpy' vs. 'sprintf'

Question

I can see many sprintf\'s used in my applications for copying a string.

I have a character array:

char myarray[10];
const char *str = \"myst         


        

Answer 1

There is one way to use sprintf() (or if being paranoid, snprintf() ) to do a "safe" string copy, that truncates instead of overflowing the field or leaving it un-NUL-terminated.

That is to use the "*" format character as "string precision" as follows:

So:

char dest_buff[32];
....
sprintf(dest_buff, "%.*s", sizeof(dest_buff) - 1, unknown_string);

This places the contents of unknown_string into dest_buff allowing space for the terminating NUL.