Development/Architecture/KDE4/Starting Other Programs - Revision history

AnneW at 18:24, 15 July 2012

2012-07-15T18:24:44Z

Pino: add system()

2009-05-29T18:07:07Z

add system()

Hualiang.miao: internationalization

2009-02-15T15:35:09Z

internationalization

Tampakrap: maybe clearer

2009-01-09T12:38:31Z

maybe clearer

Dfaure: better link

2008-12-16T12:05:05Z

better link

Dfaure: explain klauncher and dbus startuptype/servicename

2008-12-16T11:58:17Z

explain klauncher and dbus startuptype/servicename

Dfaure: fix formatting, using more standard == for headings; couldn't find any docu on the semicolon/colon syntax previously used.

2008-12-16T11:45:35Z

fix formatting, using more standard == for headings; couldn't find any docu on the semicolon/colon syntax previously used.

Dfaure: Upgraded to KDE4, added invokeBrowser.

2008-12-16T11:32:11Z

Upgraded to KDE4, added invokeBrowser.

New page

'''KDE Architecture - Starting programs'''

In KDE there are several ways to start other programs from within
your application. Here is a short summary of your options with reasons why
you should or should not use them.

;fork + exec
:You never want to use this unless you have a very good reason why it is impossible to use KProcess.

;KProcess
:You want to use [http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKProcess.html KProcess] class if you need to start a new process which needs to be a child of your process, e.g. because you want to catch stdout/stderr or need to send it data via stdin. You should never use this to start other KDE applications (unless your application is a debugger :-)

;KToolInvocation::startServiceByDesktopPath
[http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html]
:Preferred way to launch desktop (KDE/Gnome/X) applications or KDE services. The application/service must have a .desktop file. It will make use of KDEinit for increased startup performance and lower memory usage. These benefits only apply to applications available as KDEinit loadable module (KLM).

;KRun
:Generic way to open documents/applications/shell commands. Uses startServiceByDesktopPath where applicable. Offers the additional benefit of startup-notification.<br/> [http://api.kde.org/4.x-api/kdelibs-apidocs/kio/html/classKRun.html KRun] can start any application, from the binary or the desktop file, it will determine the mimetype of a file before running the preferred handler for it, and it can also start shell commands. This makes KRun the recommended way to run another program in KDE.

;KToolInvocation::invokeBrowser
[http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html]
Launches a web browser. The difference with KRun is that KRun has to determine the mimetype of the URL first (which, for HTTP, involves starting a download to read the headers), so if you know that the URL is an HTML webpage, use invokeBrowser in order to skip that step and let the
browser window show faster (the mimetype check is especially annoying if the user's preferred browser is a non-kde application like firefox, rather than konqueror, which can reuse the kioslave started by KRun).

[[Category:KDE4]]
[[Category:Architecture]]

← Older revision		Revision as of 18:24, 15 July 2012
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	'''KDE Architecture - Starting programs'''		'''KDE Architecture - Starting programs'''

@@ Line 9: / Line 9: @@
 == fork + exec ==
 You never want to use this unless you have a very good reason why it is impossible to use KProcess.
 == KProcess ==

← Older revision		Revision as of 15:35, 15 February 2009
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		+	{{Template:I18n/Language Navigation Bar\|Development/Architecture/KDE4/Starting Other Programs}}
		+
	'''KDE Architecture - Starting programs'''		'''KDE Architecture - Starting programs'''

@@ Line 22: / Line 22: @@
 == KToolInvocation::invokeBrowser ==
-[http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html KToolInvocation::invokeBrowser] launches a web browser. The difference with KRun is that KRun has to determine the mimetype of the URL first (which, for HTTP, involves starting a download to read the headers), so if you know that the URL is an HTML webpage, use invokeBrowser in order to skip that step and let the browser window show faster (the mimetype check is especially annoying if the user's preferred browser is a non-kde application like firefox, rather than konqueror, which can reuse the kioslave started by KRun).
+[http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html KToolInvocation::invokeBrowser] launches a web browser. The difference with using the more generic KRun on the webpage URL is that KRun has to determine the mimetype of the URL first (which, for HTTP, involves starting a download to read the headers), so if you know that the URL is an HTML webpage, use invokeBrowser, it will be faster.
 [[Category:KDE4]]
 [[Category:Architecture]]

@@ Line 14: / Line 14: @@
 [http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html KToolInvocation::startServiceByDesktopPath] is the preferred way to launch desktop (KDE/Gnome/X) applications or KDE services. The application/service must have a .desktop file, and you must know the name of that file. KToolInvocation asks the klauncher process, via DBUS, to start the program.
 === klauncher ===
-klauncher will wait until the application registers to DBUS if the desktop file specifies the [http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKService.html#6419c30c7fab9341c1df192621f5953a X-DBUS-StartupType] key. This allows to make DBUS calls to the application once startServiceByDesktopPath returns, without the risk of race conditions. Note that klauncher needs to know under which name the application will register to DBUS: by default that is assumed to be org.kde.<i>binaryname</i>, but you can configure this by setting X-DBUS-ServiceName in the .desktop file. If you don't, you will get an error from klauncher which will think the application failed to start, since the expected dbus name never showed up.
+klauncher will wait until the application registers to DBUS if the desktop file specifies the [http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html#_details X-DBUS-StartupType] key. This allows to make DBUS calls to the application once startServiceByDesktopPath returns, without the risk of race conditions. Note that klauncher needs to know under which name the application will register to DBUS: by default that is assumed to be org.kde.<i>binaryname</i>, but you can configure this by setting X-DBUS-ServiceName in the .desktop file. If you don't, you will get an error from klauncher which will think the application failed to start, since the expected dbus name never showed up.
 === kdeinit ===
 klauncher makes use of KDEinit for increased startup performance and lower memory usage. These benefits only apply to applications available as KDEinit loadable module (KLM).

@@ Line 12: / Line 12: @@
 == KToolInvocation::startServiceByDesktopPath ==
-[http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html KToolInvocation::startServiceByDesktopPath] is the preferred way to launch desktop (KDE/Gnome/X) applications or KDE services. The application/service must have a .desktop file, and you must know the name of that file. It will make use of KDEinit for increased startup performance and lower memory usage. These benefits only apply to applications available as KDEinit loadable module (KLM).
+[http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html KToolInvocation::startServiceByDesktopPath] is the preferred way to launch desktop (KDE/Gnome/X) applications or KDE services. The application/service must have a .desktop file, and you must know the name of that file. KToolInvocation asks the klauncher process, via DBUS, to start the program.
 == KRun ==

@@ Line 5: / Line 5: @@
 you should or should not use them.
-;fork + exec
+== fork + exec ==
-:You never want to use this unless you have a very good reason why it is impossible to use KProcess.
+You never want to use this unless you have a very good reason why it is impossible to use KProcess.
-;KProcess
+== KProcess ==
-:You want to use [http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKProcess.html KProcess] class if you need to start a new process which needs to be a child of your process, e.g. because you want to catch stdout/stderr or need to send it data via stdin. You should never use this to start other KDE applications (unless your application is a debugger :-)
+You want to use [http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKProcess.html KProcess] class if you need to start a new process which needs to be a child of your process, e.g. because you want to catch stdout/stderr or need to send it data via stdin. You should never use this to start other KDE applications (unless your application is a debugger :-)
-;KToolInvocation::startServiceByDesktopPath
+== KToolInvocation::startServiceByDesktopPath ==
-[http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html]
+[http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html KToolInvocation::startServiceByDesktopPath] is the preferred way to launch desktop (KDE/Gnome/X) applications or KDE services. The application/service must have a .desktop file, and you must know the name of that file. It will make use of KDEinit for increased startup performance and lower memory usage. These benefits only apply to applications available as KDEinit loadable module (KLM).
-:Preferred way to launch desktop (KDE/Gnome/X) applications or KDE services. The application/service must have a .desktop file. It will make use of KDEinit for increased startup performance and lower memory usage. These benefits only apply to applications available as KDEinit loadable module (KLM).
-;KRun
+== KRun ==
-:Generic way to open documents/applications/shell commands. Uses startServiceByDesktopPath where applicable. Offers the additional benefit of startup-notification.<br/> [http://api.kde.org/4.x-api/kdelibs-apidocs/kio/html/classKRun.html KRun] can start any application, from the binary or the desktop file, it will determine the mimetype of a file before running the preferred handler for it, and it can also start shell commands. This makes KRun the recommended way to run another program in KDE.
+Generic way to open documents/applications/shell commands. Uses startServiceByDesktopPath where applicable. Offers the additional benefit of startup-notification.<br/> [http://api.kde.org/4.x-api/kdelibs-apidocs/kio/html/classKRun.html KRun] can start any application, from the binary or the desktop file, it will determine the mimetype of a file before running the preferred handler for it, and it can also start shell commands. This makes KRun the recommended way to run another program in KDE.
-;KToolInvocation::invokeBrowser
+== KToolInvocation::invokeBrowser ==
-[http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html]
+[http://api.kde.org/4.x-api/kdelibs-apidocs/kdecore/html/classKToolInvocation.html KToolInvocation::invokeBrowser] launches a web browser. The difference with KRun is that KRun has to determine the mimetype of the URL first (which, for HTTP, involves starting a download to read the headers), so if you know that the URL is an HTML webpage, use invokeBrowser in order to skip that step and let the browser window show faster (the mimetype check is especially annoying if the user's preferred browser is a non-kde application like firefox, rather than konqueror, which can reuse the kioslave started by KRun).
-Launches a web browser. The difference with KRun is that KRun has to determine the mimetype of the URL first (which, for HTTP, involves starting a download to read the headers), so if you know that the URL is an HTML webpage, use invokeBrowser in order to skip that step and let the
 browser window show faster (the mimetype check is especially annoying if the user's preferred browser is a non-kde application like firefox, rather than konqueror, which can reuse the kioslave started by KRun).
 [[Category:KDE4]]
 [[Category:Architecture]]