In some of POCO libraries (Net on Windows, Data back-ends, Crypto, NetSSL …), there is a need for early library initialization. This task has been done so far in a couple of ways (neither elegant) – we either<\/p>\n
So, the question here is: can we (and, if the answer is yes, how?) improve the current state?<\/p>\n
At first, one would think this (SQLite back-end with abbreviated names used as an example here) will do the trick:<\/p>\n
}; Alas, MSVC will disregard your wishes in both static and dynamic library builds when it sees that the registrator is “not used” anywhere. Luckily, there’s a way to force the linkage:<\/p>\n With some ifdef-ing for 64-bit (no underscore decoration) and dynamic exports, it turns out that the task is achievable:<\/p>\n So, now we have a way to force initialization without having to explicitly call registerConnector from user code (or peppering library with initialization code).<\/p>\n Details are in GitHub repo<\/a> (Net and Data back-ends only at the time of this writing).<\/p>\n This modification was tested on Windows, Mac and Linux, static and shared builds; I’m putting a word out to hear comments and make sure I did not miss something important, so suggestions are more than welcome. I’d like to have this in the upcoming\u00a01.5.2<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" In some of POCO libraries (Net on Windows, Data back-ends, Crypto, NetSSL …), there is a need for early library initialization. This task has been done so far in a couple of ways (neither elegant) – we either (1) call initialization (repeatedly) from some strategic points in the library (Net, SSL) that we know will […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,26],"tags":[],"class_list":["post-741","post","type-post","status-publish","format-standard","hentry","category-development","category-tips-tricks"],"_links":{"self":[{"href":"https:\/\/pocoproject.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/741","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pocoproject.org\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pocoproject.org\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pocoproject.org\/blog\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/pocoproject.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=741"}],"version-history":[{"count":50,"href":"https:\/\/pocoproject.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/741\/revisions"}],"predecessor-version":[{"id":791,"href":"https:\/\/pocoproject.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/741\/revisions\/791"}],"wp:attachment":[{"href":"https:\/\/pocoproject.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=741"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pocoproject.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=741"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pocoproject.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=741"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}\/\/ Connector.h:<\/em>
\n struct<\/span> SQLite_API SQLiteRegistrator
\n{<\/code><\/p>\nSQLiteRegistrator()
\n{
\nSQLite::Connector::registerConnector();
\n}<\/code><\/p>\n~SQLiteRegistrator()
\n{
\nSQLite::Connector::unregisterConnector();
\n}<\/code><\/p>\n
\n
\n extern<\/span> \"C\"<\/span> struct<\/span> SQLite_API SQLiteRegistrator sqliteRegistrator;<\/code><\/p>\n <\/code><\/p>\n\/\/ Connector.cpp:<\/em>
\nSQLiteRegistrator sqliteRegistrator;<\/code><\/p>\n#pragma<\/span>(comment<\/span> (linker, \"\/include:_sqliteRegistrator\"<\/span>)<\/code><\/p>\n#pragma<\/span>(comment (linker, \"\/export:sqliteRegistrator\"<\/span>)<\/code><\/p>\n