{"id":311,"date":"2019-09-18T06:43:58","date_gmt":"2019-09-18T12:43:58","guid":{"rendered":"https:\/\/www.great-white-software.com\/blog\/?p=311"},"modified":"2019-09-19T14:02:24","modified_gmt":"2019-09-19T20:02:24","slug":"debugging-tip","status":"publish","type":"post","link":"https:\/\/www.great-white-software.com\/blog\/2019\/09\/18\/debugging-tip\/","title":{"rendered":"Debugging tip"},"content":{"rendered":"\n

Sometime when you’re debugging your application you run into a situation where you get funky behaviour. <\/p>\n\n\n\n

You might do something like Javier mentioned in his recent blog post on Xojo’s blog :<\/p>\n\n\n\n

Dim ASource() As Integer = Array(1,2,3,4,5,6,7,8)\nDim ATarget() As Integer\nATarget = ASource<\/code><\/pre>\n\n\n\n
And, as he noted, you cant figure out why when you change one array you also appear to alter the other. This can also happen with other reference types<\/a> as I noted in other posts.<\/p>\n\n\n\n
For instance I’ve seen<\/p>\n\n\n\n
Dim d As New Date\nDim d1 As date\nd1 = d\n\nd1.month = 2<\/code><\/pre>\n\n\n\n
and then the question of “why did d change?” arises<\/p>\n\n\n\n
Again this has been covered before and it has to do with both arrays and dates, as well as many other type, being reference types.<\/p>\n\n\n\n
One way to see that in fact these are the same object is not well documented in the Xojo documentation. Its buried in the Debugging pane of the preferences – Show Object IDs in variable lists.<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
Once you enable this setting what you see in the debugger pane makes it much easier to see when you have two references to the same object.<\/p>\n\n\n\n
When viewing the following code<\/p>\n\n\n\n
Dim ASource() As Integer = Array(1,2,3,4,5,6,7,8)\nDim ATarget() As Integer\nATarget = ASource<\/code><\/pre>\n\n\n\n
You can clearly see that ATarget and ASource have the same objectID. In Xojo’s runtime this means they are the same object – objectsID’s are unique to every instance and the only way you get two objectID’s that are the same is when two references refer to the same object.<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
I’d recommend always turning this setting on when debugging.<\/p>\n","protected":false},"excerpt":{"rendered":"
Sometime when you’re debugging your application you run into a situation where you get funky behaviour. You might do something like Javier mentioned in his recent blog post on Xojo’s blog : And, as he noted, you cant figure out why when you change one array you also appear to alter the other. This can … <\/p>\n
Continue reading “Debugging tip”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1],"tags":[18,6,3],"class_list":["post-311","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-debugging","tag-tips","tag-xojo"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.great-white-software.com\/blog\/wp-json\/wp\/v2\/posts\/311","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.great-white-software.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.great-white-software.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.great-white-software.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.great-white-software.com\/blog\/wp-json\/wp\/v2\/comments?post=311"}],"version-history":[{"count":5,"href":"https:\/\/www.great-white-software.com\/blog\/wp-json\/wp\/v2\/posts\/311\/revisions"}],"predecessor-version":[{"id":320,"href":"https:\/\/www.great-white-software.com\/blog\/wp-json\/wp\/v2\/posts\/311\/revisions\/320"}],"wp:attachment":[{"href":"https:\/\/www.great-white-software.com\/blog\/wp-json\/wp\/v2\/media?parent=311"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.great-white-software.com\/blog\/wp-json\/wp\/v2\/categories?post=311"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.great-white-software.com\/blog\/wp-json\/wp\/v2\/tags?post=311"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}