vsprintf — Format a string and place it in a buffer
| int vsprintf ( | char * buf, | 
| const char * fmt, | |
| va_list args ); | 
bufThe buffer to place the result into
fmtThe format string to use
argsArguments for the format string
   The function returns the number of characters written
   into buf. Use vsnprintf or vscnprintf in order to avoid
   buffer overflows.
   
   If you're not already dealing with a va_list consider using sprintf.
   
   See the vsnprintf documentation for format string extensions over C99.