public String getCallingConvention() {
		if (conventionIndex == -1) {
			return null;
		}
		return callingConvention[conventionIndex];
	}
Returns a calling convention string if the C object is determined to be a function with
a specified convention
@return the convention or {@code null} if not determined to be a function with convention
Ghidra/Features/MicrosoftDmang/src/main/java/mdemangler/object/MDObjectC.java