private TypeDef getPtrDiffT() {
		if (ptrdiff_t != null) {
			return ptrdiff_t;
		}
		ptrdiff_t = lookupTypeDef(PTRDIFF_T_NAME);
		if (ptrdiff_t == null) {
			ptrdiff_t = new TypedefDataType(PTRDIFF_T_NAME, getIntegralPointerType(true));
			Msg.warn(this, PTRDIFF_T_NAME + " not defined.  Generated as `" + ptrdiff_t + "'");
		}
		return ptrdiff_t;
	}
Skips a series of numbers (field width or precision) within a format String.
returns the index of the format String at the last digit before another
non-digit character

@param formatString format String
@param i      index into formatStr
@return new index into formatString
Ghidra/Features/DecompilerDependent/src/main/java/ghidra/app/plugin/core/string/variadic/FormatStringParser.java