{"id":1323,"date":"2014-04-04T07:00:00","date_gmt":"2014-04-04T07:00:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/oldnewthing\/2014\/04\/04\/its-bad-enough-for-a-guest-to-demolish-the-hosts-house-demolishing-an-unrelated-persons-house-is-taking-it-to-a-whole-new-level\/"},"modified":"2014-04-04T07:00:00","modified_gmt":"2014-04-04T07:00:00","slug":"its-bad-enough-for-a-guest-to-demolish-the-hosts-house-demolishing-an-unrelated-persons-house-is-taking-it-to-a-whole-new-level","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/oldnewthing\/20140404-00\/?p=1323","title":{"rendered":"It's bad enough for a guest to demolish the host's house; demolishing an unrelated person's house is taking it to a whole new level"},"content":{"rendered":"

\n“How do I destroy a window that belongs to another process?”\n<\/p>\n

\nThe Destroy­Window<\/code> function will not destroy\nwindows that belong to another thread,\nmuch less another process.\nThe best you can do is post a\nWM_CLOSE<\/code> message to the window to ask it nicely.\nThe Def­Window­Proc<\/code> function response to the\nWM_CLOSE<\/code> message by destroying the window,\nbut the window is free to add a custom handler for the\nWM_CLOSE<\/code> message which rejects the request.\n<\/p>\n

\n(If you are thinking of posting the\nWM_DESTROY<\/code> message,\nthen you’re the sort of person who\n\nprank-calls somebody pretending to be the police<\/a>.)\n<\/p>\n

\nIf you want to distinguish between user-initiated requests to close\nthe window (say, by clicking the X button in the corner),\nand your special, “No, really, just destroy the window” demand\nto close the window,\nyou can invent a private message for this purpose.\n<\/p>\n

\n#define WM_FORCECLOSE (WM_APP + 3141)\nLRESULT CALLBACK VictimWndProc(HWND hwnd, UINT uMsg,\n    WPARAM wParam, LPARAM lParam)\n{\n switch (uMsg) {\n ...\n case WM_FORCECLOSE: DestroyWindow(hwnd); return 0;\n ...\n }\n return DefWindowProc(hwnd, uMsg, wParam, lParam);\n}\nvoid ForceCloseWindow(HWND hwnd)\n{\n PostMessage(hwnd, WM_FORCECLOSE, 0, 0);\n}\n<\/pre>\n
\nOf course, this\nWM_FORCE­CLOSE<\/code> message works only\nwith windows specially designed to understand it.\n<\/p>\n
\n“I can’t do that because the window I want to force closed\nbelongs to some application I did not write,\nso I cannot modify its window procedure.”\n<\/p>\n
\nThis is another case of\n\nIf it’s not yours,\nthen don’t mess with it without permission from the owner<\/i><\/a>.\nOne of the rules of thumb for real life is that if something\ndoesn’t belong to you,\nthen you shouldn’t mess with it unless you have permission from the owner.\n<\/p>\n
\nYou need to work with the application vendor\nto come to some sort of agreement on how you can tell the\napplication to close the window unconditionally.\nOtherwise, you’re even worse than the guest who\n\nvisits a house and calls the demolition company to have the house\ndestroyed<\/a>.\nYou’re the guy who calls the demolition company to\norder the destruction of some completely unrelated house<\/i>.\n<\/p>\n
\nHow would you like it if a random person called\nthe demolition company to destroy your house?<\/p>\n","protected":false},"excerpt":{"rendered":"
“How do I destroy a window that belongs to another process?” The Destroy­Window function will not destroy windows that belong to another thread, much less another process. The best you can do is post a WM_CLOSE message to the window to ask it nicely. The Def­Window­Proc function response to the WM_CLOSE message by destroying the […]<\/p>\n","protected":false},"author":1069,"featured_media":111744,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[25],"class_list":["post-1323","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-code"],"acf":[],"blog_post_summary":"
“How do I destroy a window that belongs to another process?” The Destroy­Window function will not destroy windows that belong to another thread, much less another process. The best you can do is post a WM_CLOSE message to the window to ask it nicely. The Def­Window­Proc function response to the WM_CLOSE message by destroying the […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/1323","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/users\/1069"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/comments?post=1323"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/1323\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media\/111744"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media?parent=1323"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=1323"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=1323"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}