Returns true if the given file_name is an absolute file name.
Note that this is a somewhat vague concept on Windows.
On POSIX systems, an absolute file name is well-defined. It always starts from the single root directory. For example "/usr/local".
On Windows, the concepts of current drive and drive-specific current directory introduce vagueness. This function interprets as an absolute file name one that either begins with a directory separator such as "\Users\tml" or begins with the root on a drive, for example "C:\Windows". The first case also includes UNC paths such as "\\myserver\docs\foo". In all cases, either slashes or backslashes are accepted.
Note that a file name relative to the current drive root does not truly specify a file uniquely over time and across processes, as the current drive is a per-process value and can be changed.
File names relative the current directory on some specific drive, such as "D:foo/bar", are not interpreted as absolute by this function,
but they obviously are not relative to the normal current directory as returned by getcwd or
get_current_dir either. Such paths should be avoided, or need to be
handled using Windows-specific code.
| file_name |
a file name |
|
true if |