### 36.7 Environment Variables

getenv (var)

  Return the value of the environment variable var.

  For example,

      getenv ("PATH")

  returns a string containing the value of your path.

  See also: setenv, unsetenv.

setenv (var, value)
setenv (var)
putenv (…)

  Set the value of the environment variable var to value.

  If no value is specified then the variable will be assigned the null string.

  See also: unsetenv, getenv.

status = unsetenv (var)

  Delete the environment variable var.

  Return 0 if the variable was deleted, or did not exist, and -1 if an error occurred.

  See also: setenv, getenv.

homedir = get_home_directory ()

  Return the current home directory.

  On most systems, this is equivalent to `getenv ("HOME")`. On Windows systems, if the environment variable `HOME` is not set then it is equivalent to `fullfile (getenv ("HOMEDRIVE"), getenv ("HOMEPATH"))`

  See also: getenv.