XtOpenApplication(3)

💖 NAME 💖

okay so bestie, gather round, because XtOpenApplication and XtVaOpenApplication are the moment. They initialize, open, or close a display. That's the whole vibe. This is one of the XT FUNCTIONS pages, and it's lowkey iconic for anyone doing X Toolkit stuff. 🫶

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✨ SYNTAX ✨

no cap, the includes go like this:

#include <X11/Intrinsic.h>

Widget XtOpenApplication(XtAppContext *app_context_return, const char
       *application_class, XrmOptionDescRec *options, Cardinal
       num_options, int *argc_in_out, char **argv_in_out, String
       *fallback_resources, WidgetClass widget_class, ArgList args,
       Cardinal num_args);

Widget XtVaOpenApplication(XtAppContext *app_context_return, const char
       *application_class, XrmOptionDescRec *options, Cardinal
       num_options, int *argc_in_out, char **argv_in_out, String
       *fallback_resources, WidgetClass widget_class, ...);

two whole flavors, and yes the second one is the varargs girlie. 💅

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🎀 ARGUMENTS 🎀

• app_context_return — tells it where to put the application context. that's the assignment, bestie. 🎯
• application_class — the class name of this application, which usually is the generic name for all instances of this application. so like, the family name, not the individual. 👑
• options — specifies how to parse the command line for any application-specific resources. this argument gets passed as a parameter to XrmParseCommand. want the tea on it? go read Xlib - C Language X Interface. 📖
• num_options — how many entries live in the options list. count 'em. 🔢
• argc_in_out — a pointer to the number of command line parameters. pointer!! don't forget. 🫠
• argv_in_out — the command line parameters themselves.
• fallback_resources — resource values to be used if the application class resource file cannot be opened or read, or NULL. backup plan energy. 🧚
• widget_class — the widget class of the shell to be created. 🐚
• args — the argument list that overrides any other resource specification for the created shell widget. it said override, fr fr. ⚡
• num_args — number of entries in the argument list.
• ... — the variable argument list that overrides any other resource specification for the created shell widget. same override behavior, just the vibey version. 🌈

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🌸 DESCRIPTION 🌸

so here's the rundown, bestie. XtOpenApplication calls XtToolkitInitialize, then XtCreateApplicationContext, then it calls XtOpenDisplay with display_string set to NULL and application_name set to NULL, and finally it calls XtAppCreateShell with application_name NULL, the widget_class you specified, and the args and num_args you specified — and then it hands you back the created shell. 🐚✨

the modified argc and argv that came back from XtDisplayInitialize get returned in argc_in_out and argv_in_out. If app_context_return is not NULL, the created application context gets returned too. two-for-one, we love to see it. 🫶

🚨 okay but listen: if the display specified by the command line cannot be opened, an error message is issued and XtOpenApplication terminates the application. like, that's it, game over, no vibes. 😭

and if fallback_resources is non-NULL, XtAppSetFallbackResources is called with that value prior to calling XtOpenDisplay. order matters, periodt. 💅

the way that XtAppInitialize and XtVaAppInitialize have been superseded by XtOpenApplication and XtVaOpenApplication respectively... yeah. the old ones are giving legacy. use the new ones. ⭐

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🦋 SEE ALSO 🦋

• XtAppInitialize(3)
• XtVaAppInitialize(3)
• X Toolkit Intrinsics - C Language Interface
• Xlib - C Language X Interface

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okay bestie that's the whole page, no notes. this one shipped with X Version 11, libXt 1.3.1 — so when you're out here opening applications, just know that's the version holding it down. slay, bye 💖✨🎀🦋