{"id":13543,"date":"2010-07-01T07:00:00","date_gmt":"2010-07-01T07:00:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/oldnewthing\/2010\/07\/01\/what-is-the-lpclass-member-of-shellexecuteinfo-used-for\/"},"modified":"2010-07-01T07:00:00","modified_gmt":"2010-07-01T07:00:00","slug":"what-is-the-lpclass-member-of-shellexecuteinfo-used-for","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/oldnewthing\/20100701-00\/?p=13543","title":{"rendered":"What is the lpClass member of SHELLEXECUTEINFO used for?"},"content":{"rendered":"

\nA customer reported problems launching\nthe default Web browser with the\nShell­Execute­Ex<\/code> function:\n<\/p>\n

\nint _tmain(int argc, _TCHAR* argv[])\n{\n  SHELLEXECUTEINFO sei = {0};\n  sei.cbSize = sizeof(sei);\n  sei.nShow = SW_SHOWNORMAL;\n  sei.lpFile = TEXT(\"www.microsoft.com\");\n  sei.fMask = SEE_MASK_CLASSNAME;\n  sei.lpVerb = TEXT(\"opennew\");\n  sei.lpClass = TEXT(\"htmlfile\");\n  ShellExecuteEx(&sei);\n  return 0;\n}\n<\/pre>\n
\nThis fails with sei.hInstApp = SE_ERR_FNF<\/code>.\n<\/p>\n
\nIf you don’t pass the SEE_MASK_CLASSNAME<\/code> flag and\nleave lpClass = NULL<\/code>,\nthen the Shell­Execute­Ex<\/code> function will try to\nfigure out what your lpFile<\/code> refers to,\nlooking at the file extension,\nlooking for the file on the PATH<\/code>,\nand if all else fails,\n\ntrying some autocorrection<\/a>.\nIn this case, the customer was relying on the autocorrection,\nsince they left the http:\/\/<\/code> prefix off their URL.\nOne of the default autocorrection rules is that if the item that couldn’t\nbe launched begins with www<\/code>, then try again with\nhttp:\/\/<\/code> in front.\n<\/p>\n
\nOn the other hand,\nif you pass an explicit lpClass<\/code>,\nthen no name resolution is performed on the lpFile<\/code>.\nYou’re saying “Don’t do any sniffing and poking and autocorrection.\nI have already determined that this item should be executed according\nto the rules specified for\nHKEY_CLASSES_ROOT\\htmlfile<\/code>,\nso just follow the rules and don’t question me.”\n<\/p>\n
\nNo second-guessing means that the Shell­Execute­Ex<\/code>\nfunction shrugged its shoulders and said,\n“Well, I don’t see a file called www.microsoft.com<\/code>\nin the current directory, so I will fail with a file-not-found error.”\n<\/p>\n
\nIf you pass an explicit class, then\nShell­Execute­Ex<\/code> will\ntreat your lpFile<\/code> as if it were a file of that type.\nIf you have something and you want all the standard detection logic\nto kick in, then don’t specify a class.\n<\/p>\n
\nBonus reading<\/b>:\nThe above program is simplified to illustrate the topic.\nA real-life version of this program\n\nneeds some other scaffolding<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"
A customer reported problems launching the default Web browser with the Shell­Execute­Ex function: int _tmain(int argc, _TCHAR* argv[]) { SHELLEXECUTEINFO sei = {0}; sei.cbSize = sizeof(sei); sei.nShow = SW_SHOWNORMAL; sei.lpFile = TEXT(“www.microsoft.com”); sei.fMask = SEE_MASK_CLASSNAME; sei.lpVerb = TEXT(“opennew”); sei.lpClass = TEXT(“htmlfile”); ShellExecuteEx(&sei); return 0; } This fails with sei.hInstApp = SE_ERR_FNF. If you don’t pass […]<\/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-13543","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-code"],"acf":[],"blog_post_summary":"
A customer reported problems launching the default Web browser with the Shell­Execute­Ex function: int _tmain(int argc, _TCHAR* argv[]) { SHELLEXECUTEINFO sei = {0}; sei.cbSize = sizeof(sei); sei.nShow = SW_SHOWNORMAL; sei.lpFile = TEXT(“www.microsoft.com”); sei.fMask = SEE_MASK_CLASSNAME; sei.lpVerb = TEXT(“opennew”); sei.lpClass = TEXT(“htmlfile”); ShellExecuteEx(&sei); return 0; } This fails with sei.hInstApp = SE_ERR_FNF. If you don’t pass […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/13543","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=13543"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/13543\/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=13543"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=13543"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=13543"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}