[GRASSLIST:7163] Re: length restriction on raster names?

[Glynn Clements]

[CC'd to developers' list]

Vincent Schut wrote:

> is there a length restriction on GRASS raster names, especially when
> used in an imaginary group? I have several rasters with quite long names
> (like: '20020101_20030101_normalized_min'). I can access these fine, but
> when I add them to a group, this doesn't work and the REF file of the
> group seems garbage: the raster names looks like they have been cut at
> something around 20 characters. Is this intentional?

Looking at the imagery.h header, I notice:

	struct Ref
	{
	    int nfiles;
	    struct Ref_Files
	    {
		char name[30]; /* length is not in sync with other definitions */
		char mapset[30];
	    } *file;

That suggests that map names are limited to 30 bytes (29 bytes plus a
terminating NUL).

There isn't a global setting for the maximum length of a map name
(although there probably should be). I note that "struct Reclass"
allows for 50 bytes. Other code which allocates fixed-sized buffers
for map names commonly allocates 100, 256 or 512 bytes (the last one
is likely to exceed the maximum length of a filename on most operating
systems).

-- 
Glynn Clements <glynn at gclements.plus.com>