Length (USHORT)
A length of at least 32 bytes must be used to start a DOS session with the session type specified. A length greater than 32 is not allowed if the Session Manager detects that the Presentation Manager is not present.
When a Length of 24 or 30 bytes is specified, DosStartSession initializes the missing parameters to 0. This allows the Shell to provide values for the missing information, based on the installation file entry for the program being started.
Specify a Length of 30 bytes to use the environment and inheritance features of the system. Specify a Length of 50 bytes to specify the type of session to start, and to define data for windows.
A Length of 60 bytes allows you to use all of the functions provided by DosStartSession.