• Windows 10: WSL (Windows Subsystem for Linux)
• Windows: MinGW-w64 project or STL's MinGW distro

download page

Only newer versions are largely conforming to the modern ISO C++ standard(s).

bundled with C++Builder

• Red Hat
• Solaris

bundled with Oracle Developer Studio

• AIX
• z/OS
• z/VM

Compiler Explorer

• lets you run code through many different compilers
• shows nicely annotated assembly output
• lots of compilers with lots of different versions, also with experimental features
• offers several popular libraries
• great text editor with multiple cursors, VIM mode, dark mode, …

• gcc
• clang
• C++03 - C++2a
• Boost

• gcc 4.9
• Boost 1.55
• C++03 - 14

• C++14