Experimental Physics and
Industrial Control System

"Kasemir, Kay via Core-talk" <core-talk at aps.anl.gov> · Wed, 14 Apr 2021 15:57:23 +0000

I vaguely remember that inside code, like when calling 'open()' on a file, Windows handles /forward/slash/paths just fine, as it does handle c:\those\backslash\paths. But a path that combines / and \ might be problematic. 

If you manually set 

epicsEnvSet FOO  "C:\Users\nobody\AppData\Roaming/foobar"

does that actually work?
Or are the macro issues just part of the problem, the combined / and \ will be the next one?
Would a better workaround in this case be to define %APPDATA% with forward slashes?
Or in case %APPDATA% is some predefined variable, introduce your own variable? 

---
Under Windows, using system environment variables containing paths in the iocShell doesn't work, because backslash characters (\) in the path are interpreted as the first character of an escape sequence. 

Example. Trying to set a location inside %AppData% by doing
epicsEnvSet FOO ${APPDATA}/foobar

creates an invalid path, because the backslashes disappear:
C:UsersnobodyAppDataRoaming/foobar  

Shouldn't backslashes rather be treated verbatim here?
The expansion is done by macLib before the epicsEnvSet command is being called. Do we need a modifier that allows verbatim macro replacement? The getenv() used by macLib converts '\' to '\\' when reading from the environment, but macLib seems to resolve (discard) the "escape sequence" further down in the process.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System