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paulscherrerinstitute / StreamDevice

EPICS Driver for message based I/O
GNU General Public License v3.0
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STREAM_PROTOCOL_PATH separator #75

Closed FreddieAkeroyd closed 3 years ago

FreddieAkeroyd commented 3 years ago

In https://github.com/paulscherrerinstitute/StreamDevice/commit/98fa595753bc9d071ecad828bc41d70ab04d1954 the default separator for STREAM_PROTOCOL_PATH was changed to be ; on windows. This is more correct and avoids issues with referring to other drives like d: etc. but does mean that STREAM_PROTOCOL_PATH is no longer OS independent. I was wondering if a command to build a path in the right format could be added, so the st.cmd could then be

streamProtocolPath("dir1","dir2")

which would do an epicsEnvSet of STREAM_PROTOCOL_PATH with the appropriate OS separator

dirk-zimoch commented 3 years ago

A command to build paths would be a generally useful thing in EPICS. Actually, I have one at PSI: addPath (ENVVAR, dir), but it is not for Windows (uses : only).

dirk-zimoch commented 3 years ago

BTW: addPath() does more than simply concatinating the dirs. It pushes dir to the front, so that last added dir is found first, deletes any occurance that may already be in the variable, but always keeps an initial . in front, so that local files are always preferred to files in some other dir.

MYPATH=".:/a/b/c:/x/y:z"
addPath(MYPATH, "/new/dir")
MYPATH=".:/new/dir:/a/b/c:/x/y:z"
addPath(MYPATH, "/x/y")
MYPATH=".:/x/y:/new/dir:/a/b/c:z"
FreddieAkeroyd commented 3 years ago

Your addPath would be a useful addition in EPICS base, but it would require stream device to use a newer EPICS base if you were to use it in examples. It is only an issue on windows though, I'm not sure how many people this affects. Would you prefer just an addPath in epics base over a streamProtocolPath like command, or maybe having both would be OK?

dirk-zimoch commented 3 years ago

Is there a way to support both, : and ; as path separators on Windows, without getting confused with drive letters? Like "A single letter followed by : is a drive, not a directoy. (And / is \)" So cfg:c:/epics:\abc would split to cfg c:\epics and \abc. [I really do not like Windows.]

FreddieAkeroyd commented 3 years ago

That would cover most cases, if somebody did create a directory called "c" that would just have to make sure it was referred to as:./c: or :c/: to distinguish it from :c:\dir:

dirk-zimoch commented 3 years ago

Fixed in release 2.8.20.