MSYS2 Shells for C++

MSYS2 Shells (C++)

When you install MSYS2, it provides several different shells, each tailored for specific tasks and environments. Here’s a breakdown of the main shells available with MSYS2 and how they differ:

1. MSYS Shell (msys2.exe)

• Purpose: The MSYS shell provides a Unix-like environment and a minimal set of GNU tools designed for basic command-line operations, scripting, and using native MSYS2 utilities.
• Environment: This shell is configured for a POSIX-compatible environment and doesn’t link with the Windows C runtime (CRT). It’s closer to a traditional Unix shell.
• Use Case: Primarily used for running MSYS-specific tools and scripts, installing MSYS packages, and managing the MSYS2 environment itself.
• Limitations: This shell is not intended for compiling native Windows applications. Instead, it’s mainly for managing MSYS2 packages and running Unix-like commands that depend on POSIX compatibility.

2. MinGW 64-bit Shell (mingw64.exe)

• Purpose: This shell provides an environment for compiling 64-bit Windows-native applications using the MinGW-w64 toolchain.
• Environment: It sets up the environment to link with Windows libraries and uses the x86_64-w64-mingw32 target. This shell is ideal for building 64-bit binaries that run natively on Windows without needing any POSIX emulation.
• Use Case: Recommended for C++ development targeting 64-bit Windows applications, as it’s optimized for creating high-performance native Windows executables.
• Limitations: Less compatible with POSIX-specific code since it’s focused on native Windows compatibility.

3. MinGW 32-bit Shell (mingw32.exe)

• Purpose: This shell is designed for compiling 32-bit Windows-native applications using the 32-bit MinGW-w64 toolchain.
• Environment: Similar to the MinGW 64-bit shell, but targets the i686-w64-mingw32 platform for 32-bit binaries.
• Use Case: Useful if you need to build 32-bit applications for Windows, which might be required for legacy systems or applications with specific 32-bit dependencies.
• Limitations: Less suitable for modern applications targeting 64-bit systems and also less compatible with POSIX-style code.

4. UCRT64 Shell

• Purpose: The UCRT64 shell is part of the MinGW-w64 environment but is specifically configured to use the Universal C Runtime (UCRT) instead of the older MSVCRT. The UCRT is the modern C runtime recommended by Microsoft for newer Windows applications.
• Environment: Targets the x86_64-w64-mingw32 platform, but links against the UCRT instead of the MSVCRT, providing better standards compliance and compatibility with modern C++ standards.
• Use Case: Ideal for modern 64-bit Windows applications where C++ standards compliance is crucial. This shell is especially helpful if you need to ensure compatibility with recent versions of Windows.
• Limitations: Not compatible with POSIX-dependent code. It’s strictly for 64-bit Windows applications, so not suited for 32-bit or POSIX-specific builds.

5. CLANG64 Shell

• Purpose: The CLANG64 shell is set up to use the Clang/LLVM compiler targeting 64-bit Windows applications.
• Environment: Similar to the MinGW-w64 64-bit shell, but uses Clang as the compiler, providing different optimizations and compatibility options than GCC.
• Use Case: Useful if you prefer Clang over GCC for C++ development, as Clang offers additional diagnostics, optimizations, and compatibility with other toolchains.
• Limitations: Like other Windows-targeted shells, it’s not POSIX-compatible and is intended for native Windows development only.

Summary Table

Shell	Targeted Architecture	Compiler	Use Case	POSIX Compatibility
MSYS	MSYS2 environment	MSYS GCC	Running POSIX-style commands, managing MSYS2	Yes
MinGW 64-bit	64-bit Windows	GCC (MinGW-w64)	Compiling 64-bit native Windows applications	No
MinGW 32-bit	32-bit Windows	GCC (MinGW-w64)	Compiling 32-bit native Windows applications	No
UCRT64	64-bit Windows	GCC (UCRT)	Modern Windows apps with Universal C Runtime	No
CLANG64	64-bit Windows	Clang/LLVM	Windows apps using Clang for C++ development	No

Which Shell Should You Use?

• For Basic MSYS2 Management and POSIX Commands: Use the MSYS shell. It’s best for package management and running Unix-style commands that require a POSIX environment.
• For Building Windows-Native 64-bit C++ Applications: Use the MinGW 64-bit shell. This shell will be your primary environment if you’re developing C++ applications that should run as native Windows programs.
• For 32-bit Applications: If you specifically need to target 32-bit Windows, use the MinGW 32-bit shell.
• For Modern C++ Standards Compliance: The UCRT64 shell is a good choice if you’re building C++ applications with a focus on standards compliance and modern Windows compatibility.
• For Clang/LLVM Users: The CLANG64 shell is optimal if you prefer the Clang compiler for its diagnostics and compatibility benefits.