In addition to regular text files, you may also specify the name of a workspace file for Source Insight to open.
For example:
sourceinsight4 myset.siwork
This will open all the files in the workspace file myset.siwork.
Any number of workspace file names may also be intermixed with regular file names.
For example:
sourceinsight4 +100 file.c myset.vw print.c myset2.siwork
This will open both the files and the workspace files.