anatGetAll documentation should specify defs=NULL works and what it does

[gdevenyi]

If I don't have a defs file, anatGetAll should just use the label number from the atlas file.

[cfhammill]

It does (or should). Does this not work anymore?

https://github.com/Mouse-Imaging-Centre/RMINC/blob/master/R/minc_anatomy.R#L256

[gdevenyi]

Ah. So it does.

But it defaults to a environment variable and bails out on error if unspecified.

Also, the docs don't say NULL is allowed. :)

[cfhammill]

Oops, my fault, Sys.getenv on fail returns an empty string instead of NULL, so on other systems the default gets initialized incorrectly. I'll fix and doc, thanks for the spot.

[cfhammill]

Fixed.