Environment Variables

Following is a list of environment variables that are used or referenced by MDSplus. These are not sorted in a particular order, but are mostly grouped by relation to each other.

If you do not find an environment variable listed here, it may be specific to your site.

MDS_PATH

TDI Search Path. One or more paths separated by semicolons. TDI will search each directory for .fun and then .py files matching the name of the function being searched for.

MDSPLUS_DIR

Path to MDSplus installation. This is used for setting a lot of other variables through envsyms.

<tree>_path

The path to search for the tree files for a given tree name (where ${tree} is the name of your tree). If present, this will be used instead of default_tree_path. This variable can contain one or more paths separated by semicolons. Each path to search can be anything defined elsewhere in this documentation.

These two separate variables ($${tree}_path and default_tree_path) may be useful if you are creating your own tree outside of a tree owned by your organization; the this allows you to quickly access both.

default_tree_path

The path to search for the tree files for a tree that does not have ${tree}_path defined. One or more paths separated by semicolons. Each path to search can be anything defined elsewhere in this documentation.

TreeHooks

Used to enable a comma-separated list of tree hooks.

mds_event_target

If set, TCP events will be used instead of UDP events. This contains the event server to send the TCP events to.

MDS_HOST

This defines the default server/host to connect to when a host is not specified to the mdsconnect() function.

TCP_WINDOW_SIZE

If set, this will be used by setsockopt() to set both SO_RCVBUF and SO_SNDBUF in bytes, which are two Linux OS settings. The default is 32KB.

MDSIP_MAX_VERSION

If set when running mdsip, this will be used when accepting connections to limit the MDSip protocol version. Note: this is separate from the MDSplus version. It is not recommended to set this to any value and this variable may be removed at a later date.

MDSIP_SERVICE_LOGDIR

When using mdsip_service.exe to set up an MDSip server on Windows, this controls where the log files will be written to.

MDSIP_SERVER_LOGDIR

This does not control where log files are written, but rather indicates where they already are. This is used to find available servers with wildcards in certain circumstances.

MDSIP_CONNECT_TIMEOUT

When set, this will be used as the timeout in seconds for all connections. If not specified, the default value is 10 seconds.

UDP_EVENTS

This is deprecated and unused.

DEBUG_DEVICES

Setting this to a non-zero value will enable debug output from most MDSplus devices.

PYDEVICE_ADD_SOURCE

If set to yes, when adding a device to the tree, the python source code will be included in the tree as well. Method calls on this device node in the tree will not require the device source code to be installed.

MDS_PYDEVICE_PATH

This is a semicolon-separated list of paths to search for python MDSplus device source code when adding a device. Each path will be searched recursively for device classes by importing all files that end with .py and do not begin with _. Only subclasses of MDSplus.Device will be considered when searching.

MDSPLUS_VERSION_CHECK

If set to 0, off, or no this will disable the version check when importing the MDSplus package in python. If enabled, the version check will warn if the version of MDSplus the python package was intended for is not being used.

PyLib

Path to the python development library, used to run python code from within MDSplus. If not specified, the default is python2.7.

Can accept any of the following formats:

name (e.g., python3.10)
filename (e.g., libpython3.10.so)
full path (e.g., /usr/lib64/libpython3.10.so)

MDSPLUS_DEFAULT_RESAMPLE_MODE

Selects the resample mode to be used by default when reading segmented records from nodes that do not have the ResampleMode XNCI present. The default is Average.

The options are:

Average
MinMax
Interpolation
Closest
Previous

PRINTER

The default printer to use when printing a scope with dwscope. Defaults to To file.

MDS_LIB_PS

The path to a setup postscript file to be prepended to your document when printing. Defaults to $MDSPLUS_DIR/lib/dwscope_setup.ps.

A4PAPER

If set to any value, A4 paper dimensions (210x297mm or 8.27x11.69”) will be used when printing (as opposed to 8.5x11”).

SHELL

Used when spawning shell commands in the form of $SHELL -c "command". Defaults to /bin/sh.

HISTFILESIZE

Used by tdic to limit the number of lines stored in the $HOME/.tdic history file. Refer to www.gnu.org/software/bash/manual/bash.html#index-HISTFILESIZE. On Windows, the history file is called %LocalAppData%\tdic.

MACHINE

This will be returned by the TDI machine() function. Potentially indicates the fusion device the current environment is configured for.

MDSMSG_PATH

A single path to search for libraries which contain additional error messages. Library files matching $MDSMSG_PATH/*Msg.* and containing a symbol named getmsg will be used. The default is $MDSPLUS_DIR/lib.

Example: libMyStatusMsg.so

int getmsg(int sts, char **facnam, char **msgnam, char **msgtext)
{
    if (sts == MY_STATUS_CODE) {
        *facnam = "MY";
        *msgnam = "STATUS_CODE";
        *msgtext = "My Status Code.";
        return SUCCESS;
    }

    return FAILURE;
}

IDL_PATH

The default is +$MDSPLUS_DIR/idl:<IDL_DEFAULT>:$IDL_PATH.

MATLABPATH

The default is $MDSPLUS_DIR/matlab:$MATLABPATH.

PYTHONPATH

The default is $PYTHONPATH:$MDSPLUS_DIR/pydevices.

JavaMdsLib

Used by the mdsobjects java library to find libJavaMds.* to be passed to System.load(). This library contains the JNI (Java Native Interface) bindings for MDSplus.

UIDPATH

The default is /usr/local/mdsplus/uid.

SYBASE_HOST

SQL database host, used by mdssql.pro, dbinfo.pro, and entry_display.pro

UDP_EVENTS

Allegedly the way to enable/disable UDP events, but no library code references it This is deprecated and unused.

NEXT_ROW_FIX

Replaced with TreeSetRowsFilled function therefore no reason to call out

ExcludeMitCamacDevices

If set to a non-empty value, it will disable Camac devices when running MITDEVICES().

ExcludeMitObsoleteDevices

If set to a non-empty value, it will disable Obsolete devices when running MITDEVICES().