/proc support, and even on systems *with* ProcFS support. Return
nonzero if the failure may be legitimate, e.g., because /proc is not
readable, or the particular .../fd/N directory is not present. */
/proc support, and even on systems *with* ProcFS support. Return
nonzero if the failure may be legitimate, e.g., because /proc is not
readable, or the particular .../fd/N directory is not present. */