The caret character is a special in cmd.exe on Windows

[qhuo]

The caret character (^) is a great feature of ninja, which allows one to build the object file specifying only the source file. However, as it is a special character in cmd.exe, it is very awkward to use on Windows. One has to 2 carets when invoking ninja on Windows cmd windows. And the number of carets have to be doubled or redoubled depending on how many levels of system() call (or cmd.exe invocation) are involved. In our case, we have a wrapper program, which runs ninja either locally or through the Incredibuild engine, so we have to use 4 or 8 carets characters.

It would be great if another character can be chose for this feature, or better yet, create a command line option for this.

[evmar]

The reason I didn't use a command-line option in the first place is because (in theory) you could do something like
ninja foo.o bar.cc^
and control it on a per-argument basis. That is pretty weak, though.

Is there a different character on Windows that will make it through, but that doesn't often exist in filenames?

[evmar]

Maybe some prefix would work, like "output:foo.cc"

[qhuo]

@martine, personally I don't mind losing the ability of mixing normal target and the output(^) on the same command line.

But if you are looking for a new special charater, cmd's help doc says the following special characters require quotes, &()[]{}^=;!'+,`~ and . Perhaps we can use "@"? This is a valid char for file names on both windows and linux, but I suppose it's not often used.

[ddevienne]

@file is often used for "response file" though, to put long command line switches into a file, and thus work-around CLI limitations of some shells.

[qhuo]

@ddevienne, yes, but this should not prevent ninja taking path/to/foo.cpp@ as a command line argument. As far as I know, ninja does not pass foo.cpp@ to any of the build actions.