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GeneralRe: Device on RS232 only responds to first send request (Visual C++) Pin
jeron127-Sep-16 13:28
jeron127-Sep-16 13:28 
GeneralRe: Device on RS232 only responds to first send request (Visual C++) Pin
David MacKinnon28-Sep-16 12:30
David MacKinnon28-Sep-16 12:30 
GeneralRe: Device on RS232 only responds to first send request (Visual C++) Pin
jeron129-Sep-16 4:19
jeron129-Sep-16 4:19 
GeneralRe: Device on RS232 only responds to first send request (Visual C++) Pin
David MacKinnon29-Sep-16 4:43
David MacKinnon29-Sep-16 4:43 
AnswerRe: Device on RS232 only responds to first send request (Visual C++) Pin
leon de boer27-Sep-16 17:18
leon de boer27-Sep-16 17:18 
GeneralRe: Device on RS232 only responds to first send request (Visual C++) Pin
David MacKinnon29-Sep-16 4:45
David MacKinnon29-Sep-16 4:45 
AnswerRe: Device on RS232 only responds to first send request (Visual C++) Pin
David MacKinnon29-Sep-16 4:40
David MacKinnon29-Sep-16 4:40 
Question_tcscpy_s and unused buffer part Pin
leon de boer27-Sep-16 5:39
leon de boer27-Sep-16 5:39 
If anyone has a minute can they confirm a weird behaviour of _tcscpy_s which caught me totally off guard that it trashes the unused part of the return buffer.

The code I would like you to test follows, you will need include TCHAR.H for the standard _tcscpy_s function
#include <TCHAR.H>

TCHAR szFilter[512];

memset(szFilter, 0, sizeof(szFilter));   // Zero szFilter
_tcscpy_s(szFilter, _countof(szFilter), _T("All files"));
int i = _tcslen(szFilter);
TCHAR Ch1 = szFilter[i + 2];      // Place a debug here .. Ch1 will be trash .. my nice zeroed buffer is toast

memset(szFilter, 0, sizeof(szFilter));    // Zero szFilter
_tcscpy_s(szFilter, _tcslen(_T("All files"))+1, _T("All files"));
TCHAR Ch2 = szFilter[i + 2];      // Place a debug here .. Ch2 will be 0 as expected


What I am interested in is the part of the buffer the result is not written in. What stunned me was it was all trashed.
Okay the function does not define what it does with the unused parts of the buffer but it seems a waste of time to play with it.
The stranger part is if you lie to the function and make it have just the right size buffer it doesn't trash the buffer.

It's so quirky I am trying to work out if it is a machine/processor dependent implementation of the function.
In vino veritas

AnswerRe: _tcscpy_s and unused buffer part Pin
Richard MacCutchan27-Sep-16 6:26
mveRichard MacCutchan27-Sep-16 6:26 
GeneralRe: _tcscpy_s and unused buffer part Pin
leon de boer27-Sep-16 18:36
leon de boer27-Sep-16 18:36 
AnswerRe: _tcscpy_s and unused buffer part Pin
Richard MacCutchan27-Sep-16 6:33
mveRichard MacCutchan27-Sep-16 6:33 
AnswerRe: _tcscpy_s and unused buffer part Pin
Chris Losinger27-Sep-16 7:28
professionalChris Losinger27-Sep-16 7:28 
GeneralRe: _tcscpy_s and unused buffer part Pin
leon de boer27-Sep-16 20:24
leon de boer27-Sep-16 20:24 
GeneralRe: _tcscpy_s and unused buffer part Pin
David Crow27-Sep-16 8:20
David Crow27-Sep-16 8:20 
GeneralRe: _tcscpy_s and unused buffer part Pin
leon de boer27-Sep-16 18:35
leon de boer27-Sep-16 18:35 
QuestionRe: _tcscpy_s and unused buffer part Pin
David Crow28-Sep-16 2:35
David Crow28-Sep-16 2:35 
AnswerRe: _tcscpy_s and unused buffer part Pin
leon de boer28-Sep-16 17:47
leon de boer28-Sep-16 17:47 
GeneralRe: _tcscpy_s and unused buffer part Pin
David Crow28-Sep-16 18:09
David Crow28-Sep-16 18:09 
GeneralRe: _tcscpy_s and unused buffer part Pin
leon de boer28-Sep-16 18:14
leon de boer28-Sep-16 18:14 
GeneralRe: _tcscpy_s and unused buffer part Pin
David Crow29-Sep-16 3:10
David Crow29-Sep-16 3:10 
AnswerRe: _tcscpy_s and unused buffer part Pin
Joe Woodbury24-Oct-16 14:36
professionalJoe Woodbury24-Oct-16 14:36 
QuestionArrow Key use in MFC vc++ Application Pin
rajmohan 12327-Sep-16 2:38
rajmohan 12327-Sep-16 2:38 
AnswerRe: Arrow Key use in MFC vc++ Application Pin
Chris Losinger27-Sep-16 3:26
professionalChris Losinger27-Sep-16 3:26 
GeneralRe: Arrow Key use in MFC vc++ Application Pin
rajmohan 12327-Sep-16 20:05
rajmohan 12327-Sep-16 20:05 
QuestionHow do you get type from format? Pin
Vaclav_26-Sep-16 5:03
Vaclav_26-Sep-16 5:03 

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