Tchar

TCHAR is a typedef defined in the Windows header tchar.h that provides a generic character type intended to simplify writing code that can be compiled for either ANSI or Unicode character sets. When UNICODE (and often _UNICODE) is defined, TCHAR resolves to wchar_t; otherwise it resolves to char. This enables code to handle text with a single type regardless of build configuration.

The tchar.h header also defines related generic string and pointer types, such as LPTSTR (pointer to TCHAR) and LPCTSTR (pointer to const TCHAR), as well as a family of character and string function macros that map to the narrow or wide versions, including _tcslen, _tcscpy, and _tprintf. String literals can be written with the TEXT or _T macro, which expands to L"..." in Unicode builds and "..." in ANSI builds.

The generic entry points and utilities mirror this mapping: _tmain maps to main or wmain, and _tWinMain maps to WinMain or wWinMain, depending on the build. Code written with TCHAR and the _t* functions is portable between Unicode and non-Unicode configurations.

Usage notes: TCHAR originated to ease porting between ANSI and Unicode Windows APIs and to support older codebases. In modern Windows development, using wchar_t with the wide-character APIs, or explicit UTF-8 workflows with appropriate conversions, is often preferred. TCHAR remains available for maintaining legacy code and for projects that rely on the Windows SDK’s traditional text abstractions. See tchar.h for the full set of types and macros, and for how UNICODE and _UNICODE influence mappings.