What is proj_read_write field?

[ma81x]

I'm developing an application that modifies project db tables and I
want my app manages lock fields like MSP do. Reading prjdb.htm file
helped me a lot, but I still have a dubt:
what does mean proj_read_write? and how doesit works?
When I open a proj in read_write mode, MSP increment it by 1; when I
open in read_only MSP increment it by 2.
Why? And how have I to manage it?

Thanks.

(Sorry for english)

 

[JackD]

1 means read write. 2 means read only. I believe 0 is not open.
Why they chose those numbers I do not know.

 

[Cory K. Walker]

This field is used by MSP 2003 to check if the project is already opened for
read and write access. Your application will likely need to set this field
if there are other users that will try to open the project with MSP. MSP
will stop users from saving changes to the project.

Keep in mind that this stops MSP and other conformant applications from
writing to the database. A person could easily write another application
that could completely ignore this field.