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LaunchWebBrowser() problem and perhaps not the best solution [message #35714]

Wed, 14 March 2012 11:40

koldo
Messages: 3453
Registered: August 2008

Senior Veteran

Hello all

In my XP LaunchWebBrowser() does not work because of ShellExecute.

A possible solution proposed here ( http://stackoverflow.com/questions/1193873/which-reasons-cou ld-make-shellexecute-fail) is to create a separate thread for executing ShellExecute.
The reason could be this one(Calling Shell Functions and Interfaces from a Multithreaded Apartment: http://support.microsoft.com/?scid=kb%3Ben-us%3B287087&x =16&y=15).

The solution works for me. First call to ShellExecuteOpen() fails but second one in a separate thread, works.
However I am not sure if it is a right implementation. Please check it before approve.

#if defined(PLATFORM_WIN32) && !defined(PLATFORM_WINCE)
bool ShellExecuteOpen(const char *str)
{
	return 32 < int(ShellExecuteW(NULL, L"open", ToSystemCharsetW(str), NULL, L".", SW_SHOWDEFAULT));
}

void LaunchWebBrowser(const String& url)
{
	if (!ShellExecuteOpen(url)) {
		HANDLE handle = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)&ShellExecuteOpen, (LPVOID)~url, 0, NULL);
		if (handle == NULL)
			return;
		WaitForSingleObject(handle, 500);
		CloseHandle(handle);
	} 
}
#endif

Best regards
Iñaki

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Re: LaunchWebBrowser() problem and perhaps not the best solution [message #35731 is a reply to message #35714]

Wed, 14 March 2012 22:37

mirek
Messages: 14271
Registered: November 2005

Ultimate Member

koldo wrote on Wed, 14 March 2012 06:40

#if defined(PLATFORM_WIN32) && !defined(PLATFORM_WINCE)
bool ShellExecuteOpen(const char *str)
{
	return 32 < int(ShellExecuteW(NULL, L"open", ToSystemCharsetW(str), NULL, L".", SW_SHOWDEFAULT));
}

void LaunchWebBrowser(const String& url)
{
	if (!ShellExecuteOpen(url)) {
		HANDLE handle = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)&ShellExecuteOpen, (LPVOID)~url, 0, NULL);
		if (handle == NULL)
			return;
		WaitForSingleObject(handle, 500);
		CloseHandle(handle);
	} 
}
#endif

Looks quite OK with me. Maybe the WaitForSingleObject is not needed...

Mirek

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Re: LaunchWebBrowser() problem and perhaps not the best solution [message #35737 is a reply to message #35731]

Thu, 15 March 2012 08:41

koldo
Messages: 3453
Registered: August 2008

Senior Veteran

Hello Mirek

In fact WaitForSingleObject() is useless as it always wait the timeout.

However I realized that sometimes the string passed is released BEFORE the thread is really run so second call to ShellExecuteW() fails as LaunchWebBrowser() has ended before Smile

.

The proposed solution is this one:

void ShellExecuteOpen(char *str)
{
	ShellExecuteW(NULL, L"open", ToSystemCharsetW(str), NULL, L".", SW_SHOWDEFAULT);
	free((void *)str);
}

void LaunchWebBrowser(const String& url)
{
	if (int(ShellExecuteW(NULL, L"open", ToSystemCharsetW(url), NULL, L".", SW_SHOWDEFAULT)) <= 32) {
		char *curl = (char *)malloc(url.GetLength()+1);
		strcpy(curl, url);
		HANDLE handle = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)&ShellExecuteOpen, (LPVOID)curl, 0, NULL);
		if (handle == NULL)
			return;
		CloseHandle(handle);
	} 
}

The thread receives the string and releases it.

Best regards
Iñaki

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Re: LaunchWebBrowser() problem and perhaps not the best solution [message #35946 is a reply to message #35737]

Sun, 08 April 2012 16:15

koldo
Messages: 3453
Registered: August 2008

Senior Veteran

Hello Mirek

Could you check this?

Best regards
Iñaki

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Re: LaunchWebBrowser() problem and perhaps not the best solution [message #35953 is a reply to message #35946]

Sun, 08 April 2012 17:02

mirek
Messages: 14271
Registered: November 2005

Ultimate Member

I have found a bug, IMO you should not have to use ToSystemCharsetW in thread, if you want this to work in U++ single-threaded mode...

After fixing this, commited.

Also used new "raw thread support".

Please check.

Mirek

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