LVDefs_plat.h contains basic constants and macros that the LabVIEW C Generator needs to generate C code. This file provides the mapping between generic C function calls that the C Generator generates and platform-specific, run-time functions. LVDefs_plat.h also contains platform definitions of data types for the compiler.
The C Generator includes an example LVDefs_plat.h file for several platforms. If you are using one of the example platforms, you can use the installed LVDefs_plat.h file for that platform instead of creating a new file. The LVDefs_plat.h files are located in platform-specific folders in the labview\CCodeGen\include\platform directory.
The example LVDefs_plat.h files include comments that explain what you must define for the platform. To properly define data types, you must know the compiler definitions of those data types. Refer to the documentation for the compiler to determine those values. To define the generic function calls, you must know how the target SDK implements these function calls. Refer to the SDK documentation for the target to define these function calls.