lib/gis: add documentation for G_wait()

[nilason]

lib/gis: add documentation for G_wait()

(Would have been useful for #7847.)

[Valyrian-Code]

Sorry, I misread this as an issue, you had already written it.

One thing the docblock does not say is that "process exit code" differs by platform. POSIX returns WEXITSTATUS, so 0-255, while Windows returns GetExitCodeProcess cast to int, so any value including negatives. That is what let an exit code collide with a negative sentinel in #7847.

[echoix]

Sorry, I misread this as an issue, you had already written it.

One thing the docblock does not say is that "process exit code" differs by platform. POSIX returns WEXITSTATUS, so 0-255, while Windows returns GetExitCodeProcess cast to int, so any value including negatives. That is what let an exit code collide with a negative sentinel in #7847.

Would you have a wording suggestion to add to the change, so it can be reviewed by Nicklas?

[nilason]

I don’t see anything needs to change here, it is obvious as it is.