Re: HOME directory

[Glynn Clements <glynn@gclements.plus.com>]

HIToC wrote:

> 	I am writing a piece of code that makes files, open directories in my
> HOME directory. All worked well until I changed the name of my HOME dir.
> To make the code portable I tried with use of '~' character:
> 
> 	const char*	filename = "~/file.txt";
> 	ofstream	 my_file(filename, ios::out);
> 
> but this solution does not work.
> Have you any suggestion to find the path of the current home directory or
> the current user name?

The "~" syntax is part of the shell; library functions won't expand
it. In the shell, "~/..." is equivalent to "$HOME/...".

If you want to respect $HOME (which is usually the case), use e.g.:

	const char *home = getenv("HOME");
	const char *file = "file.txt";
	char *path = alloca(strlen(home) + strlen(file) + 2);

	sprintf(path, "%s/%s", home, file);

	ofstream my_file(filename, ios::out);

If you want to always use the user's home directory from /etc/passwd
instead of $HOME (e.g. for setuid programs), use getpwuid(), e.g.:

	struct passwd *pw = getpwuid(getuid());
	if (!pw)
		fatal_error("user not listed in /etc/passwd");
	const char *home = pw->pw_dir;

	...

Similarly, the ~user syntax for a specific user's home directory is
implemented using getpwnam().

-- 
Glynn Clements <glynn@gclements.plus.com>