About wavein API - C / C++ / MFC Discussion Boards

Re: Using handle between two process

Nishad S9-Jan-08 23:52

Nishad S

9-Jan-08 23:52

Yes you can use it. But when using it, take care about the operations. You cant use all APIs, or messages directly.

- NS -
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Re: Using handle between two process

ashtwin10-Jan-08 1:19

ashtwin

10-Jan-08 1:19

Hi,
thanks u all for replying. Currently i am using FindWindow() to get the handle of a dialog and using that handle i am sending the message(using PostMessage api)to this dialog(which is part of seperate process). As of now it is working fine.

Thanks

Re: Using handle between two process

Nishad S10-Jan-08 1:43

Nishad S

10-Jan-08 1:43

welcome...

I remember your post before... this[^]

- NS -
[ODBaseBtn]

Re: Using handle between two process

CPallini10-Jan-08 2:16

CPallini

10-Jan-08 2:16

ashtwin wrote:
Currently i am using FindWindow() to get the handle of a dialog and using that handle i am sending the message(using PostMessage api)to this dialog(which is part of seperate process). As of now it is working fine.

It should work fine.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

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Re: Using handle between two process

David Crow10-Jan-08 2:19

David Crow

10-Jan-08 2:19

ashtwin wrote:
Hi, i am using FindWindow() function to get the handle of a dialog in one process from some other process. Can anybody tell is that correct or any problem...

Technically it will work, but you risk a deadlock situation if the target window is in a blocked state.

"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman

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Re: Using handle between two process

ashtwin10-Jan-08 18:32

ashtwin

10-Jan-08 18:32

Hi,
in ur view which API can cause the deadlock(FindWindow() or PostMessage()).
I don't think that PostMessage() can cause a deadlock.

Thanks

Re: Using handle between two process

David Crow11-Jan-08 2:29

David Crow

11-Jan-08 2:29

FindWindow() internally sends each top-level window a WM_GETTEXT message. But if the thread that owns that window is blocked (e.g., a Semaphore, a Mutex, an Event, an I/O operation), SendMessage() will block until that thread frees up and runs. Since this could potentially never happen, FindWindow() will block forever.

About wavein API

minihotto9-Jan-08 23:26

minihotto

9-Jan-08 23:26

Hello
I have a program using waveIn API.
This is part of my code.
Originally, my program has a deadlock while running waveInReset.
I google it and it is said putting the wavein function in the callback function is forbidden.
So I delete the code which I put waveinstop in the callback function.
It can run waveInReset and waveInunprepareheader successfully.
But it halt at waveInClose.
I can't find information about waveInClose halt.
Can anybody solve this problem?Thx,
Jane.

<br />
while(1){      if(isopen==1){<br />
        if(waveInOpen(&hWavin,WAVE_MAPPER, &wfx,(DWORD_PTR)WaveInProc ,0,  CALLBACK_FUNCTION) ==   <br />
        MMSYSERR_NOERROR)<br />
         {<br />
               <br />
                isopen=1;<br />
                 for(int i=0;i<4;i++)<br />
                { <br />
                   mmrr = waveInPrepareHeader(hWavin, headersend + i, sizeof(WAVEHDR));<br />
                   mmrr = waveInAddBuffer(hWavin, headersend + i, sizeof(WAVEHDR));<br />
               }<br />
                mmrr = waveInStart(hWavin);   <br />
             }<br />
        }<br />
        if(isclose==1)<br />
        {   <br />
            if(hWavin)<br />
            {                   <br />
            mmrr=waveInReset(hWavin);<br />
                         <br />
            for(int i=0;i<4;i++)<br />
            {<br />
<br />
                mmrr=waveInUnprepareHeader(hWavin,headersend+i, sizeof(WAVEHDR));<br />
            }                <br />
           for(int i=0;i<4;i++)<br />
            {<br />
                    mmrr=waveInReset(hWavin);<br />
               }  <br />
           mmrr=waveInClose(hWavin);<br />
           sclose=0;<br />
               <br />
            }<br />
        }<br />
}<br />
static void CALLBACK WaveInProc(HWAVEIN hw, UINT uMsg,DWORD_PTR dwInstance, DWORD_PTR dwParam1, DWORD dwParam2)<br />
{<br />
         WAVEHDR* curhdrin = (WAVEHDR*)dwParam1;<br />
        if(uMsg != WIM_DATA)<br />
             return;<br />
        if(isclose==1){<br />
<br />
            Sleep(1000);<br />
            return;<br />
        }<br />
            ///other code////<br />
        waveInAddBuffer(hw, curhdrin, sizeof(WAVEHDR));<br />
<br />
}

Re: About wavein API

Mark Salsbery10-Jan-08 7:38

Mark Salsbery

10-Jan-08 7:38

How does isclose ever get set to 1?

Why is there no waveInStop() call anywhere?

Why do you use the Sleep() call in the waveInProc?
That's really going to mess things up if isclose==1.

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: About wavein API [modified]

minihotto10-Jan-08 17:49

minihotto

10-Jan-08 17:49

Thx for ur reply.
I have a button that would let user click to stop recording.
That would make isclose = 1;

Originally, I use waveInStop but I waveInStop only stop recording.
waveInReset would stop recording and set the position to 0.
I see some information in the Internet that says use waveInUnPrepareHeader before using waveInReset.

Originally, I don't use Sleep() function,but it has same problem.

I write it in a new small program as follow.
It halts at waveInReset.
If I delete waveInReset, waveInUnPrepareHeader and waveInClose falses and returns 33.

#include "stdafx.h"<br />
#include <winsock2.h><br />
#include <windows.h><br />
#include <iostream><br />
#include <mmsystem.h><br />
#pragma comment(lib, "ws2_32.lib")<br />
#pragma comment(lib, "Winmm.lib")<br />
using namespace System;<br />
using namespace std;<br />
static void CALLBACK WaveInProc(HWAVEIN, UINT,  DWORD , DWORD , DWORD );<br />
<br />
static const int SNDNBUF = 2;<br />
static const int SNDSIZEBUF = 320;<br />
HWAVEOUT hWavout;<br />
MMRESULT mmrr;<br />
WAVEHDR headersend[SNDNBUF];<br />
char hdrDatasend[SNDSIZEBUF*SNDNBUF];<br />
HWAVEIN hWavin;<br />
<br />
int _tmain(int argc, _TCHAR* argv[])<br />
{<br />
			WAVEFORMATEX wfx; <br />
			 wfx.nSamplesPerSec = 8000;<br />
			 wfx.nChannels = 1;<br />
			 wfx.wFormatTag = WAVE_FORMAT_PCM;<br />
			 wfx.wBitsPerSample = 16;<br />
			 wfx.nBlockAlign = wfx.nChannels * (wfx.wBitsPerSample / 8);<br />
			 wfx.nAvgBytesPerSec = wfx.nSamplesPerSec * wfx.nBlockAlign;<br />
<br />
	memset(headersend, 0,sizeof(WAVEHDR)*SNDNBUF);<br />
			 for(int i=0;i<sndnbuf;i++){<br />
				 headersend[i].lpData = hdrDatasend + i*SNDSIZEBUF;<br />
 				 headersend[i].dwBufferLength =  SNDSIZEBUF;}<br />
<br />
			  memset(hdrDatasend,0,SNDSIZEBUF*SNDNBUF);<br />
			<br />
			if(waveInOpen(&hWavin,WAVE_MAPPER, &wfx,(DWORD_PTR)WaveInProc ,0,  CALLBACK_FUNCTION) == MMSYSERR_NOERROR){<br />
 				for(int i=0;i<sndnbuf;i++)>{  <br />
				   mmrr = waveInPrepareHeader(hWavin, headersend + i, sizeof(WAVEHDR));<br />
				   mmrr = waveInAddBuffer(hWavin, headersend + i, sizeof(WAVEHDR));}<br />
				mmrr = waveInStart(hWavin);	}<br />
			int i;<br />
			cin >> i;<br />
			mmrr=waveInStop(hWavin);<br />
			mmrr=waveInReset(hWavin);<br />
			Sleep(500);<br />
			for(int i=0;i<sndnbuf;i++){<br />
				if ((headersend+i)->dwFlags & WHDR_PREPARED){<br />
			mmrr=waveInUnprepareHeader(hWavin,headersend+i, sizeof(WAVEHDR));}<br />
			Sleep(500);<br />
mmrr=waveInClose(hWavin);<br />
				cin >> i;<br />
	return 0;<br />
}<br />
<br />
static void CALLBACK WaveInProc(HWAVEIN hw, UINT uMsg,DWORD_PTR dwInstance, DWORD_PTR dwParam1, DWORD dwParam2)<br />
{<br />
		 WAVEHDR* curhdrin = (WAVEHDR*)dwParam1;<br />
		if(uMsg != WIM_DATA)return;<br />
		waveInAddBuffer(hw, curhdrin, sizeof(WAVEHDR));<br />
		return;<br />
}</sndnbuf;i++)></mmsystem.h></iostream></windows.h></winsock2.h>

Jane

modified on Friday, January 11, 2008 4:23:59 AM

Re: About wavein API

Mark Salsbery11-Jan-08 6:51

Mark Salsbery

11-Jan-08 6:51

The order should be:

waveInStop
waveInReset
waveInUnprepareHeader (for all buffers)

And get rid of the Sleep() calls. There is absolutely NO reason for them.

When you prepare the headers, you must initialize dwFlags (Use 0 for input
buffers) as well as lpData and dwBufferLength.

Also, IMO, "headersend + i" is confusing to read. I'd use "&headersend[i]".

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Read a file which is located in another machine

CodingLover9-Jan-08 23:13

CodingLover

9-Jan-08 23:13

Hi all,

I want to get a file path(say a text file) to read and do some processing on it. So the file path is like this, as an example.

"G:\\Work On\\CPP\\ReadFolder\\Data.txt"

So I want to change this path to refer another PC. How can I do it.

I appreciate your help all the time...
Eranga Smile | :)

Re: Read a file which is located in another machine

toxcct9-Jan-08 23:19

toxcct

9-Jan-08 23:19

change to something like this :

\\\\The_Machine_Name\\TheSharedFolder$\\Work On\\CPP\\ReadFolder\\Data.txt

for instance :

\\\\10.248.0.50\\C$\\Temp\\temp.txt

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Re: Read a file which is located in another machine

CodingLover9-Jan-08 23:35

CodingLover

9-Jan-08 23:35

Thanks, that is what I have tried. But it not work. I check the error codes, get 123 - The file name, directory name, or volume label syntax is incorrect.

Then I removed $ and test, error code is 5, says access denied. Actually I have permission to access that machine.

I appreciate your help all the time...
Eranga Smile | :)

Re: Read a file which is located in another machine

Maxwell Chen9-Jan-08 23:26

Maxwell Chen

9-Jan-08 23:26

To replace the path but keep the same file name, do the below.

CString sOri = "C:\\Tmp\\Hello.txt"; // Actually the value is from some approach.
CFile file(sOri, CFile::modeRead);
CString sNew = "\\\\192.168.0.3\\doc\\; // Get from some approach.
sNew += file.GetFileName(); // Result in "\\\\192.168.0.3\\doc\\Hello.txt".

Maxwell Chen

Re: Read a file which is located in another machine

CodingLover9-Jan-08 23:54

CodingLover

9-Jan-08 23:54

Ok, I solve this and found these things.

1) Should be shared
2) Should login as Admin to the file containing PC
3) Should have rite permission

What you guys think on my conclusion.

I appreciate your help all the time...
Eranga Smile | :)

Re: Read a file which is located in another machine

David Crow10-Jan-08 2:26

David Crow

10-Jan-08 2:26

Eranga Thennakoon wrote:
1) Should be shared
2) Should login as Admin to the file containing PC

Connecting via the admin share (C$) will get it done, but it would be better to create a specific share, and user account, for just what you need.

Eranga Thennakoon wrote:
3) Should have rite permission

Not necessary if all you're doing is reading from the file.

Re: Read a file which is located in another machine

toxcct10-Jan-08 5:14

toxcct

10-Jan-08 5:14

DavidCrow wrote:
Eranga Thennakoon wrote:
3) Should have rite permission

Not necessary if all you're doing is reading from the file.

but by rite, he meant write or right ? Wink | ;)

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Re: Read a file which is located in another machine

David Crow10-Jan-08 5:30

David Crow

10-Jan-08 5:30

toxcct wrote:
he meant write or right ?

Yep!

Re: Read a file which is located in another machine

toxcct10-Jan-08 5:38

toxcct

10-Jan-08 5:38

DavidCrow wrote:
Yep!

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Re: Read a file which is located in another machine

CodingLover10-Jan-08 16:09

CodingLover

10-Jan-08 16:09

Sorry about that Wink | ;)

missing 'w'

I appreciate your help all the time...
Eranga Smile | :)

Re: Read a file which is located in another machine

CodingLover10-Jan-08 15:57

CodingLover

10-Jan-08 15:57

DavidCrow wrote:

Not necessary if all you're doing is reading from the file.

Yes it is. Since I read it no need. It's my fault. I got that conclusion when I'm writing something to a file. Smile | :)

I appreciate your help all the time...
Eranga Smile | :)

reg. editbox

mail2h.jain9-Jan-08 23:10

mail2h.jain

9-Jan-08 23:10

how can i get the character inserted last in the edit box control.

last inserted character doesn't mean the last character of the corresponding string variable.

Re: reg. editbox

Maxwell Chen9-Jan-08 23:12

Maxwell Chen

9-Jan-08 23:12

Handle the keydown (WM_KEYDOWN) event.

Maxwell Chen

Re: reg. editbox

Hamid_RT9-Jan-08 23:25

Hamid_RT

9-Jan-08 23:25

Can you use of GetWindowText for get string of edit ctrl?

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.