4.2 - Function Reference

The LabJack driver file is named LabJackUD.dll, and contains the functions described in this section.

Some parameters are common to many functions:

• LJ_ERROR – A LabJack specific numeric errorcode. 0 means no error. (long, signed 32-bit integer).
• LJ_HANDLE – This value is returned by OpenLabJack, and then passed on to other functions to identify the opened LabJack. (long, signed 32-bit integer).

To maintain compatibility with as many languages as possible, every attempt has been made to keep the parameter types very basic. Also, many functions have multiple prototypes. The declarations that follow, are written in C.

To help those unfamiliar with strings in C, these functions expect null terminated 8 bit ASCII strings. How this translates to a particular development environment is beyond the scope of this documentation. A const char * is a pointer to a string that won’t be changed by the driver. Usually this means it can simply be a constant such as “this is a string”. A char * is a pointer to a string that will be changed. Enough bytes must be preallocated to hold the possible strings that will be returned. Functions with char * in their declaration will have the required length of the buffer documented below.

Pointers must be initialized in general, although null (0) can be passed for unused or unneeded values. The pointers for GetStreamData and RawIn/RawOut requests are not optional. Arrays and char * type strings must be initialized to the proper size before passing to the DLL.