A GUID and a CLSID and an IID are all the same as a UUID, but there are separate functions for converting a string into a GUID, CLSID, IID, and UUID. Are they all equivalent? If not, what’s the difference? And which one should I use? <\/p>\n
The basic form for a UUID string is Let’s start with Next up is Slightly more complicated is Last is Let’s summarize in a table, since that seems to be popular. I added a final column describing whether the function available in A\/W variants or is Unicode-only. <\/p>\n Mostly the same if what you have is a stringized GUID; otherwise…<\/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-91351","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-code"],"acf":[],"blog_post_summary":" Mostly the same if what you have is a stringized GUID; otherwise…<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/91351","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=91351"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/91351\/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=91351"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=91351"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=91351"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx<\/code> where each x<\/code> is a hexadecimal digit, case-insensitive. (I personally prefer all-uppercase.) All of the parsing functions under discussion use this basic form as their basis of exploration. Some functions expect the basic form to be enclosed in curly braces; others do not. <\/p>\nUuidFromString<\/code>. It takes a string in basic form without<\/i> curly braces. As a special case, if you pass NULL<\/code> instead of a valid string pointer, the function still succeeds and sets the result to GUID_NULL<\/code>. <\/p>\nIIDFromString<\/code>. This function takes a string in basic form with<\/i> curly braces. It also has the behavior that passing NULL<\/code> as the string results in success and GUID_NULL<\/code>. <\/p>\nCLSIDFromString<\/code>. In addition to accepting a brace-enclosed string (which is treated as a GUID), it also accepts a ProgId. In the ProgId case, it returns the CLSID associated with that ProgId<\/a>. For example, if you ask for Paint.Picture<\/code>, it will return the GUID {D3E34B21-9D75-101A-8C3D-00AA001A1652}<\/code>. As with the other functions, passing NULL<\/code> is valid and results in GUID_NULL<\/code>. <\/p>\nGUIDFromString<\/code>. This function is one of those “Not guaranteed to be supported beyond Windows Vista” functions, so you should probably steer clear. (Another clue that calling it is probably a bad idea: The function is not exposed in any header file or import library.) But if you insist: It accepts a brace-enclosed string, and NULL<\/code> is not<\/i> allowed. Furthermore, it ignores any garbage after the trailing brace. This function was not intended for public consumption<\/a>, so these strange quirks are not entirely unexpected. <\/p>\n\n
\n Function<\/th>\n Expected format<\/th>\n NULL allowed?<\/th>\n Character set support<\/th>\n<\/tr>\n \n UuidFromString<\/code><\/td>\nxxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx<\/code><\/td>\nYes<\/td>\n ANSI and Unicode<\/td>\n<\/tr>\n \n IIDFromString<\/code><\/td>\n{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}<\/code><\/td>\nYes<\/td>\n Unicode only<\/td>\n<\/tr>\n \n CLSIDFromString<\/code><\/td>\n{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}<\/code>
ProgId<\/code><\/td>\nYes<\/td>\n Unicode only<\/td>\n<\/tr>\n \n GUIDFromString<\/code><\/td>\n{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}*<\/code><\/td>\nNo<\/td>\n ANSI and Unicode<\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":"