zig/test/standalone/windows_argv

Tests that Zig's std.process.ArgIteratorWindows is compatible with both the MSVC and MinGW C runtimes' argv splitting algorithms.

The method of testing is:

• Compile a C file with wmain as its entry point
• The C wmain calls a Zig-implemented verify function that takes the argv from wmain and compares it to the argv gotten from std.proccess.argsAlloc (which takes kernel32.GetCommandLineW() and splits it)
• The compiled C program is spawned continuously as a child process by the implementation in fuzz.zig with randomly generated command lines
  • On Windows, the 'application name' and the 'command line' are disjoint concepts. That is, you can spawn foo.exe but set the command line to bar.exe, and CreateProcessW will spawn foo.exe but argv[0] will be bar.exe. This quirk allows us to test arbitrary argv[0] values as well which otherwise wouldn't be possible.

Note: This is intentionally testing against the C runtime argv splitting and not CommandLineToArgvW, since the C runtime argv splitting was updated in 2008 but CommandLineToArgvW still uses the pre-2008 algorithm (which differs in both argv[0] rules and ""; see here for details)

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In addition to being run during zig build test-standalone, this test can be run on its own via zig build test from within this directory.

When run on its own:

• -Diterations=<num> can be used to set the max fuzzing iterations, and -Diterations=0 can be used to fuzz indefinitely
• -Dseed=<num> can be used to set the PRNG seed for fuzz testing. If not provided, then the seed is chosen at random during build.zig compilation.

On failure, the number of iterations and the seed can be seen in the failing command, e.g. in path\to\fuzz.exe path\to\verify-msvc.exe 100 2780392459403250529, the iterations is 100 and the seed is 2780392459403250529.