Bug: cannot use "~" in path. calls fail.

Okay, I'm just about done with my mill upgrades. Just one more oddity that doesn't seem to jive with the docs.

I have a couple directories that store files

~/linuxcnc/mfiles (in the m path)
~/linuxcnc/subs (in the subroutine path, where I'm having an issue, atm)
~/linuxcnc/ncfiles (this is the program_prefix directory)
~/linuxcnc/ncfiles/ngcgui_lib (also an issue)
~/linuxcnc/ncfiles/ngcgui_lib/utilitysubs
~/linuxcnc/ncfiles/

In my display:

PROGRAM_PREFIX = /home/anthony/linuxcnc/ncfiles


In my [RS274NGC]:

SUBROUTINE_PATH = ~/linuxcnc/subs:~/linuxcnc/ncfiles/ngcgui_lib:~/linuxcnc/ncfiles/ngcgui_lib/utilitysubs
USER_M_PATH = ~/linuxcnc/mfiles:~/linuxcnc/ncfiles/ngcgui_lib/mfiles

Both Axis/NGCGUI can load files from all my paths. However, When I finalize and attempt to load auto.ngc, I get a complaint that and subroutines not located in the program prefix (ncfiles) cannot open file <name here>.

Switching each path from ~ to /home/anthony fixed those issues.

tilde expansion for ini entries like:
[RS274NGC]SUBROUTINE_PATH
and
[RS274NGC]USER_M_PATH

became available for git-master with commits like:


git.linuxcnc.org/gitweb?p=linuxcnc.git;a...4b49af684a6983629574


git.linuxcnc.org/gitweb?p=linuxcnc.git;a...65b1f829ffda0548f0ce

(so not available with current 2.5.2 or earlier)

Hi

Expansion of the tilde symbol does not happen in several cases, it can be a pain.
I have had to put in specific paths in just the same situation as you.

As well as the case you mentioned, using a string like "~/test.txt" to write a file can sometimes create a directory '~' in the current working directory, with the file test.txt inside it, not what was intended!
EDIT: (didn't explain why)
The crux of the problem is that the tilde expansion is something bash does, so does not work outside of that environment.
C libraries have no idea what it is, so system("echo 123456789 > ~/myhome.txt"); will probably work whereas fptr = fopen("~/myhome.txt", w); fwrite(fptr,"123456789"); will not.

To reliably get the home directory of the current user in C programs, you need to get the password struct and get homedir from that
#include <pwd.h>
struct passwd *pw = getpwuid(getuid());
const char *homedir = pw->pw_dir;

The environment variable HOME is generally available and in a lot of cases (certainly in scripts) the string
$HOME/linuxcnc/ncfiles will work instead of ~/linuxcnc/ncfiles for example

Try echo $HOME in a terminal and it should show your home dir

regards

Offending entries are at: linuxcnc.org/docs/html/gui/ngcgui.html

There's some emc2 references, also.