Function getenv 

pub fn getenv(variable: impl AsRef<OsStr>) -> Option<OsString>

Returns the value of an environment variable.

On UNIX, the name and value are byte strings which might or might not be in some consistent character set and encoding. On Windows, they are in UTF-8. On Windows, in case the environment variable’s value contains references to other environment variables, they are expanded.

variable

the environment variable to get

Returns

the value of the environment variable, or None if the environment variable is not found. The returned string may be overwritten by the next call to g_getenv(), g_setenv() or g_unsetenv(). Returns the value of an environment variable.

On UNIX, the name and value are byte strings which might or might not be in some consistent character set and encoding. On Windows, they are in UTF-8. On Windows, in case the environment variable’s value contains references to other environment variables, they are expanded.

variable

the environment variable to get

Returns

the value of the environment variable, or None if the environment variable is not found. The returned string may be overwritten by the next call to g_getenv(), g_setenv() or g_unsetenv().