14.6.3 Variables Affecting Check-in and Check-out

If vc-suppress-confirm is non-nil, then C-x C-q and C-x v i can save the current buffer without asking, and C-x v u also operates without asking for confirmation. (This variable does not affect C-x v c; that is so drastic that it should always ask for confirmation.)

VC mode does much of its work by running the shell commands for RCS and SCCS. If vc-command-messages is non-nil, VC displays messages to indicate which shell commands it runs, and additional messages when the commands finish.

Normally, VC assumes that it can deduce the locked/unlocked state of files by looking at the file permissions of the work file; this is fast. However, if the RCS or SCCS subdirectory is actually a symbolic link, then VC does not trust the file permissions to reflect this status.

You can specify the criterion for whether to trust the file permissions by setting the variable vc-mistrust-permissions. Its value may be t (always mistrust the file permissions and check the master file), nil (always trust the file permissions), or a function of one argument which makes the decision. The argument is the directory name of the RCS or SCCS subdirectory. A non-nil value from the function says to mistrust the file permissions.

If you find that the file permissions of work files are changed erroneously, set vc-mistrust-permissions to t. Then VC always checks the master file to determine the file’s status.

You can specify additional directories to search for version control programs by setting the variable vc-path. These directories are searched before the usual search path. The proper result usually happens automatically.