man.postnix Miscellaneous man pages of Plan 9 related material

     FD2PATH(2)                                             FD2PATH(2)

     NAME
          fd2path - return file name associated with file descriptor

     SYNOPSIS
          #include <u.h>
          #include <libc.h>

          int fd2path(int fd, char *buf, int nbuf)

     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. Up to nbuf bytes of the name are stored in buf; if the
          name is too long, it will be silently truncated at a UTF-8
          character boundary.  The name is always null-terminated.
          The return value of fd2path will be zero unless 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, getwd(2) is implemented by opening . and exe-
          cuting fd2path on the resulting file descriptor.

     SOURCE
          /sys/src/libc/9syscall

     SEE ALSO
          bind(1), ns(1), bind(2), intro(2), getwd(2), proc(3)

     DIAGNOSTICS
          Sets errstr.

     Page 1                       Plan 9            (printed 10/28/25)