Module labjack 

LabJack T7 connection and handle-inspection helpers for the streamer binary.

The streamer only supports direct Ethernet opens by IP address; it never runs LJM device discovery. These helpers handle environment parsing, device verification, stale stream cleanup, and conversion of LabJack handle metadata into readable values.

Configuration

• LABJACK_IP - IPv4 address of the T7. Required unless LABJACK_IDENTIFIER holds an IPv4 address.
• LABJACK_IDENTIFIER - Fallback for LABJACK_IP, used only when it parses as an IPv4 address.
• LABJACK_SERIAL - Expected serial number. When set, a device with another serial is rejected. ANY or a non-numeric value disables the check.
• LABJACK_NAME - Logical device name. Only logged.

For all of these, surrounding whitespace is trimmed, and an empty value or ANY (any case) counts as unset.

Constants

STREAM_IS_ACTIVE_ERROR 🔒

LJM error code returned when a stream is already active on the handle (STREAM_IS_ACTIVE).

Functions

env_identifier 🔒

Returns an environment identifier unless it is empty or the wildcard ANY.

env_var 🔒

Returns a trimmed environment variable value when set and non-empty.

handle_info

Reads LabJack metadata for an open handle.

handle_ip_address

Converts the signed IPv4 bits in LabJack handle info to dotted decimal text.

is_stream_active_error 🔒

Returns true when an LJM error indicates a stale active stream.

ljm_error_code 🔒

Extracts the numeric LJM code from an LJMError when present.

open_labjack_from_env

Opens the configured LabJack for the default streamer path.

open_streamer_labjack_from_env

Opens, verifies, and self-tests the LabJack configured by environment.

parse_ipv4 🔒

Parses an IPv4 string used by the direct Ethernet LabJack path.

requested_labjack_serial_from_env 🔒

Reads an optional expected LabJack serial number from LABJACK_SERIAL.

required_labjack_ip_from_env 🔒

Reads the required LabJack IP address from environment variables.