When I am using uVision 4.21 to check project source files. I found some files have a key on the file icon. It looks like the file is locked and user can not edit it.
My question is:
How to lock / unlock a source(*.c) file?
http://www.keil.com/support/man/docs/uv4/uv4_ca_filegrp_att.htm
Thank you for the link. It helps.