VIM src/misc1.c

vim_getenv is VIM's version of getenv().

The three variables $HOME, $VIM and $VIMRUNTIME are treated specially if the corresponding environment variable does not exist:

For HOME, the value of the global variable homedir is returned.

init_homedir tries to determine the value for VIM's $HOME variable.

The value of $HOME will be set to that of the environment variable HOME, if available.

On Windows, there is typically no HOME environment variable. Therefore, if init_homedir finds no HOME environment variable on Windows, it tries to assign the concatenation of HOMEDRIVE and HOMEPATH to PATH. If this still fails, the value of %USERPROFILE% is assigned, etc.

If all fails, the value C:\ will be assigned.

The value that was determined is assigned to the global variable static char_u *homedir` (externally defined in globals.h).

init_homedir() might be called again if encoding changes.

The code of init_homedir is duplicated in dosinst.c (to be kept in sync…)

vim_version_dir has one parameter, char_u *vimdir. The function checks if the directory vimdir/<version> or vimdir/runtime exists.

If it does not exist, the function returns NULL, otherwise, it returns the directory name in allocated memory.

Beep…