xref: /inferno-os/man/2/sys-fd2path (revision 46439007cf417cbd9ac8049bb4122c890097a0fa)
FD2PATH 2
NAME
fd2path - return file name associated with file descriptor
SYNOPSIS
.EX include "sys.m"; sys := load Sys Sys->PATH; fd2path(fd: ref FD): string;
DESCRIPTION
As described in intro (2), the kernel stores a rooted path name with every open file or directory; typically, it is the name used in the original access of the file. Fd2path returns the path name associated with open file descriptor fd . (It returns nil if an error occurs.)

Changes to the underlying name space do not update the path name stored with the file descriptor. Therefore, the path returned by fd2path may no longer refer to the same file (or indeed any file) after some component directory or file in the path has been removed, renamed or rebound.

As an example, workdir (2) is implemented by opening . and executing fd2path on the resulting file descriptor.

SEE ALSO
bind (1), ns (1), sys-bind (2), sys-intro (2), workdir (2), prog (3)
DIAGNOSTICS
Fd2path returns nil on error and sets the system error string.