Question

I’m calling Microsoft’s _wspawnv function, and it keeps returning -1 with errno set to 22; errno.h defines this as EINVAL. According to Microsoft’s documentation for _wspawnv, this code should only be returned if the mode parameter is invalid. I’ve tried calling it with _P_WAIT and _P_NOWAIT in the first parameter, and both return the same error.

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Edit: It’s amazing how many problems can be solved by going away for a day. It didn’t take me long to realize that the filename in the second parameter had quotes around it. Took them out, problem solved.

Moral of the story – don’t trust the documentation to tell you everything. I didn’t spend a lot of time double-checking the filename because the documentation didn’t list it as a possible suspect, even though the error code implied that any parameter might be invalid.

Answer 1

Oddly, the documentation also states:

If execution is allowed to continue, these functions set errno to EINVAL, and return -1. No new process is spawned.

How much of it should be trusted?

Also, it isn’t supposed to return EINVAL. It sets errno to EINVAL.