{"id":6563,"date":"2026-04-30T10:37:02","date_gmt":"2026-04-30T09:37:02","guid":{"rendered":"https:\/\/gdksoftware.com\/?page_id=6563"},"modified":"2026-04-30T10:41:55","modified_gmt":"2026-04-30T09:41:55","slug":"moving-from-ansistring-to-unicodestring-in-delphi","status":"publish","type":"page","link":"https:\/\/gdksoftware.com\/nl\/moving-from-ansistring-to-unicodestring-in-delphi","title":{"rendered":"Moving from AnsiString to UnicodeString in Delphi"},"content":{"rendered":"

If your organization is running a Delphi application developed in version 2007 or older<\/a>, you are sitting on a “Pre-Unicode” codebase. In 2009, Embarcadero<\/a> introduced a fundamental change that redefined the very fabric of the Delphi language: the switch from AnsiString to UnicodeString as the default string type.<\/strong><\/p>\n

While this change was necessary to support global character sets and modern Windows APIs, it remains the single biggest technical hurdle in legacy migration.<\/p>\n

Why the Shift is More Than “Just a Recompile”<\/h3>\n

Before Delphi 2009, a string was essentially a Byte array where one character equaled one byte. In the Unicode world, a string (now WideString\/UnicodeString) uses UTF-16 encoding, where a character typically occupies two bytes.<\/p>\n

This shift impacts your code in three critical areas:<\/p>\n

1. Pointer Arithmetic and Buffer Sizes<\/h4>\n

If your code calculates buffer sizes based on string length (e.g., Length(MyString)<\/code>), it may now be off by a factor of two. Hardcoded logic that assumes SizeOf(Char) = 1<\/code> will result in memory corruption or “buffer overflows” because, in modern Delphi, SizeOf(Char)<\/code> is 2.<\/p>\n

2. Windows API Calls<\/h4>\n

Legacy applications often call Windows API functions (like SendMessage<\/code> or GetWindowText<\/code>). Older code specifically targeted the “A” (Ansi) versions of these functions. To maintain compatibility and performance, these should be updated to the “W” (Wide\/Unicode) variants, or the underlying data handling must be carefully marshaled.<\/p>\n

3. Data Integrity and External Integrations<\/h4>\n

When your application communicates with external DLLs, file streams, or older databases, it expects a specific byte-stream format. If you send a 2-byte Unicode string to a system expecting a 1-byte Ansi string, you won’t just get weird characters (like “mojibake<\/a>“), but you risk crashing the integration or corrupting the database entirely.<\/p>\n

The Danger of Manual Conversion<\/h3>\n

The risk of a manual conversion is “silent failure.” Your application might compile successfully, but it could fail at runtime when a user enters a special character or when a specific file is processed. Auditing millions of lines of code for SizeOf<\/code> errors or incorrect pointer math is a monumental task that often takes months and carries a high risk of human error.<\/p>\n

The GDK Approach: Precision Through Automation<\/h3>\n

At GDK Software, we have refined a methodology to navigate the Unicode minefield without the manual headache. We don’t just “find and replace”; we use a data-driven approach to ensure structural integrity.<\/p>\n

Our GDK Duster tool<\/a> is specifically programmed to recognize patterns that indicate Unicode risks. Duster scans the codebase for risky patterns, such as pointer arithmetic on strings, Move()<\/code> operations, and legacy API calls. Instead of a developer having to manually investigate every string usage, Duster applies proven solutions from our extensive database to refactor the code to be Unicode-compliant.<\/p>\n

As recently announced, this automated approach is now available for C++Builder projects as well. We use the C++ compiler to catch errors and apply our “solution database” to bridge the gap between Borland C++ 4\/5\/6 and the modern Embarcadero environment.<\/p>\n

Secure Your Data, Modernize Your Code<\/h3>\n

The transition from Ansi to Unicode is the most “dangerous” part of a Delphi upgrade, but it is also the most rewarding. It opens the door to modern web services, internationalization, and 64-bit performance.<\/p>\n

Don’t let the fear of corrupted data hold your software back. Let GDK Software provide the roadmap and the tools to make your transition seamless.<\/p>\n

Ready to modernize?<\/h3>\n

Explore our Delphi Upgrade Services or see how we upgrade legacy Borland C++ applications.<\/p>\n","protected":false},"excerpt":{"rendered":"

If your organization is running a Delphi application developed in version 2007 or older, you are sitting on a “Pre-Unicode” codebase. In 2009, Embarcadero introduced a fundamental change that redefined the very fabric of the Delphi language: the switch from AnsiString to UnicodeString as the default string type. While this change was necessary to support […]<\/p>\n","protected":false},"author":4,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-6563","page","type-page","status-publish","hentry"],"acf":{"type_hero":"img","hero_image":6566,"hero_image_position":"","hero_title":"Moving from AnsiString to UnicodeString in Delphi","hero_content":"","hero_link":null,"hero_show_h1":false,"flexible_content":null},"yoast_head":"\nMoving from AnsiString to UnicodeString in Delphi - GDK Software<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/gdksoftware.com\/nl\/moving-from-ansistring-to-unicodestring-in-delphi\" \/>\n<meta property=\"og:locale\" content=\"nl_NL\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Moving from AnsiString to UnicodeString in Delphi\" \/>\n<meta property=\"og:description\" content=\"If your organization is running a Delphi application developed in version 2007 or older, you are sitting on a “Pre-Unicode” codebase. 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