Solved

What is parameter 4 in WriteFile()

Posted on 2000-02-22
1
406 Views
Last Modified: 2008-03-06
I face a problem to insert the proper lpNumberOfBytesWritten which is the parameter 4 in WriteFile(). after build, it show error "cannot convert parameter 4 from 'int *' to 'unsigned long *'. i'm sending 1 byte of data to hDevice. WriteFile(hDevice,nPtr,1,1,NULL). what's wrong with the command?
thanks.
0
Comment
Question by:giggs11
1 Comment
 
LVL 22

Accepted Solution

by:
nietod earned 50 total points
ID: 2548677
The problem is that an int is signed, but it wants an unsigned value (actually a pointer to an unsigned value.)  Since the parameter is declared as LPDWORD (i.e a pointer to a DWORD) Try

DWORD BytWrt;

WriteFile(hDevice,nptr,1,&BytWrt,NULL)
0

Featured Post

Live: Real-Time Solutions, Start Here

Receive instant 1:1 support from technology experts, using our real-time conversation and whiteboard interface. Your first 5 minutes are always free.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Written by John Humphreys C++ Threading and the POSIX Library This article will cover the basic information that you need to know in order to make use of the POSIX threading library available for C and C++ on UNIX and most Linux systems.   [s…
Many modern programming languages support the concept of a property -- a class member that combines characteristics of both a data member and a method.  These are sometimes called "smart fields" because you can add logic that is applied automaticall…
The viewer will learn how to pass data into a function in C++. This is one step further in using functions. Instead of only printing text onto the console, the function will be able to perform calculations with argumentents given by the user.
The viewer will learn additional member functions of the vector class. Specifically, the capacity and swap member functions will be introduced.

786 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question