{"id":6253,"date":"2012-10-25T07:00:00","date_gmt":"2012-10-25T07:00:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/oldnewthing\/2012\/10\/25\/keyboard-layouts-arent-like-beetlejuice-they-wont-appear-just-because-you-say-their-name\/"},"modified":"2012-10-25T07:00:00","modified_gmt":"2012-10-25T07:00:00","slug":"keyboard-layouts-arent-like-beetlejuice-they-wont-appear-just-because-you-say-their-name","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/oldnewthing\/20121025-00\/?p=6253","title":{"rendered":"Keyboard layouts aren't like Beetlejuice – they won't appear just because you say their name"},"content":{"rendered":"

\nA customer reported a bug in Windows Vista Home Editions:\n<\/p>\n

\n

\nWe are handling a Ctrl<\/kbd>+V<\/kbd>\nkeyboard event and want to interpret it in the\ncontext of a US-English keyboard.\n<\/p>\n

\n\/\/ This keyState represents no keys pressed except for Ctrl\nBYTE keyState[256] = {0};\nkeyState[VK_CONTROL] = 0x80;\n\/\/ This is the handle for the US-English keyboard\nHKL hkl = (HKL) 0x04090409;\n\/\/ output variables\nwchar_t outChar[2];\nWORD outWord;\nToUnicodeEx('V', 47, keyState, outChar, 2, 0, hkl);\nToAsciiEx('V', 47, keyState, &outWord, 0, hkl);\nVkKeyScanEx('V', hkl);\n<\/pre>\n
\nOn Windows XP and versions of Windows Vista other than Home editions,\nthe three calls all succeed, whereas on Windows Vista Home Editions,\nthe calls fail.\nOn the other hand, if instead of using the US-English keyboard,\nwe use the current keyboard layout:\n<\/p>\n
\nHKL hkl = GetKeyboardLayout(GetCurrentThreadId());\n<\/pre>\n
\nthen Windows Vista Home Editions behave the same as\nWindows XP and non-Home editions of Vista.\n<\/p>\n
\nThis suggests that the Home Editions of Vista supports keyboard\nqueries only for the currently active keyboard layout,\nwhich renders useless the last parameter to those three functions.\n<\/p>\n<\/blockquote>\n
\nNotice how the customer’s sample code just synthesizes a keyboard\nlayout handle from thin air.\nWhile it is true that\n\nthe format keyboard layout handles is documented<\/a>,\nthat doesn’t mean that you can just make one up\nand start using it.\n<\/p>\n
\nIt’s like saying,\n“I know that Contoso uses the email address format\nFirstname.Lastname@contoso.com, but I just tried to send email to\nBob.Smith@contoso.com, and it bounced.”\n<\/p>\n
\n— Does Bob work at Contoso?<\/i>\n<\/p>\n
\n“No. Does that matter?”\n<\/p>\n
\nThe customer’s code blindly assumes that the US-English keyboard layout\nis loaded rather than calling\nLoad­Keyboard­Layout<\/code> to actually load it.\nAs a result, if the keyboard layout is not loaded,\nthe call will fail because you passed an invalid keyboard layout handle.\n<\/p>\n
\nThe customer liaison asked,\n“Is this documented somewhere that the HKL has to be created\nfrom only from the functions and cannot be assigned a value?”\n<\/p>\n
\nUm, yeah, it’s right there\n\nin the documentation<\/a>\nof the hkl<\/code> parameter to the\nTo­Unicode­Ex<\/code>\nfunction.\n(Emphasis mine.)\n<\/p>\n
\n
\ndwhkl<\/i> [in, optional]\n<\/p>\n
\nType: HKL<\/b>\n<\/p>\n
\nThe input locale identifier used to translate the specified code.\nThis parameter can be any input locale identifier\npreviously returned by the Load­Keyboard­Layout<\/b> function<\/u>.\n<\/p>\n<\/blockquote>\n
\nIdentical text appears in the documentation of the\nhkl<\/code> parameter to the\nTo­Ascii­Ex<\/code> and\nVk­Key­Scan­Ex<\/code> functions as well.\n<\/p>\n
\nThe difference observed on Windows Vista Home Editions, then,\nis that on those systems, in the configurations the customer happens\nto be using, US-English is not a preloaded keyboard layout.<\/p>\n","protected":false},"excerpt":{"rendered":"
A customer reported a bug in Windows Vista Home Editions: We are handling a Ctrl+V keyboard event and want to interpret it in the context of a US-English keyboard. \/\/ This keyState represents no keys pressed except for Ctrl BYTE keyState[256] = {0}; keyState[VK_CONTROL] = 0x80; \/\/ This is the handle for the US-English keyboard […]<\/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-6253","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-code"],"acf":[],"blog_post_summary":"
A customer reported a bug in Windows Vista Home Editions: We are handling a Ctrl+V keyboard event and want to interpret it in the context of a US-English keyboard. \/\/ This keyState represents no keys pressed except for Ctrl BYTE keyState[256] = {0}; keyState[VK_CONTROL] = 0x80; \/\/ This is the handle for the US-English keyboard […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/6253","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=6253"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/6253\/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=6253"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=6253"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=6253"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}