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Date: Mon, 01 Feb 1999 21:57:16 -0500
To: djgpp AT delorie DOT com
From: Paul Derbyshire <pderbysh AT usa DOT net>
Subject: Clarification of some errno values.
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Reply-To: djgpp AT delorie DOT com

Two questions:
1. What do these errno values actually mean and where might they
   occur? In all cases the description in the info files is terse and
   not very informative.
   E2BIG      'Argument list too long'   -- is this to do with
                                            varargs?
   ECHILD     'No child processes'       -- What the heck? Pipe
                                            related?
   EFAULT     'Bad address'              -- Not a memory address,
                                            which causes SIGSEGV...
                                            raw disk address?
   EFBIG      'File too large'           -- File too large???
   EINTR      'Interrupted system call'  -- ???
   EISDIR     'Is a directory'           -- file opening related?
   EMLINK     'Too many links'           -- ???
   ENFILE     'Too many open files in system'
                                         -- How is this distinct
                                            from EMFILE?
   ENOLCK     'No locks available'       -- Where does this come
                                            from?
   ENOMEM     'Not enough memory'        -- Does malloc() do this
                                            when it returns 0?
   ENOSYS     'Function not implemented' -- ???
   ENOTDIR    'Not a directory'          -- Trying to treat a file
                                            as a directory?
   ENOTEMPTY  'Directory not empty'      -- Does it only let you
                                            rmdir an empty dir?
   ENOTTY     'Inappropriate I/O control operation'
                                         -- ??? (seek() on PRN:?)
   ENXIO      'No such device or access' -- How is this distinct
                                            from ENODEV?
   ESPIPE     'Invalid seek'             -- seek() on a pipe?
   ESRCH      'No such process'          -- ???
   EXDEV      'Improper link'            -- ???
   ENMFILE    'No more files'            -- ??? (related to the dir
                                            operations that fetch
                                            filenames
                                            sequentially?)


2. Is every last one of these macros ANSI standard and dependable?
   If not, which macros may only exist on some platforms?

-- 
   .*.  "Clouds are not spheres, mountains are not cones, coastlines are not
-()  <  circles, and bark is not smooth, nor does lightning travel in a
   `*'  straight line."    -------------------------------------------------
        -- B. Mandelbrot  |http://surf.to/pgd.net
_____________________ ____|________     Paul Derbyshire     pderbysh AT usa DOT net
Programmer & Humanist|ICQ: 10423848|