this value bit-by-bit. Each character in the format represents an argument to be collected, and the characters themselves indicate the type of the argument. Currently supported arguments are:
'i': Integers, passed ascollect_values[].v_int'l': Longs, passed ascollect_values[].v_long'd': Doubles, passed ascollect_values[].v_double'p': Pointers, passed ascollect_values[].v_pointerIt should be noted that for variable argument list construction, ANSI C promotes every type smaller than an integer to an int, and floats to doubles. So for collection of short int or char,'i'needs to be used, and for collection of floats'd'.