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 errno(2)                                                           errno(2)

 NAME    [Toc]    [Back]
      errno - error indicator for function calls

 SYNOPSIS    [Toc]    [Back]
      #include <errno.h>

 DESCRIPTION    [Toc]    [Back]
      Many functions in the HP-UX operating system indicate an error
      condition by returning an otherwise out-of-range value (usually -1).
      Most of these functions set the symbol errno, that is defined in
      errno.h, to a nonzero code value that more specifically identifies the
      particular error condition that was encountered.

      In most cases, the manpages for functions that set errno list those
      errno values and error descriptions in the ERRORS section of the
      manpages.  However, failures in underlying functions, subsystems, and
      applications may return errno values that are not documented in the
      calling functions' manpages.

      The value of errno is zero immediately after a successful call to any
      of the functions described by exec(2) and ptrace(2), but it is never
      set to zero by any other HP-UX function.  Functions for which the use
      of errno is not described may nevertheless change its value to a
      nonzero value.

      Since errno is not cleared on successful function calls, its value
      should be checked or used only when an error has been indicated and
      when the function's ERRORS section documents the error codes.

      Applications should not attempt to take the address of errno.  The
      practice of defining errno as extern int errno is obsolescent.

      The following is a complete list of the error codes.  The numeric
      values can be found in <errno.h> but they should not be used in an
      application program because they can vary from system to system.

      [E2BIG]        Arg list too long.  An argument and or environment list
                     longer than maximum supported size is presented to a
                     member of the exec() family.  Other possibilities
                     include: message size or number of semaphores exceeds
                     system limit (msgop, semop), or too many privileged
                     groups have been set up (setprivgrp).

      [EACCES]       Permission denied.  An attempt was made to access a
                     file or IPC object in a way forbidden by the protection

      [EADDRINUSE]   Address already in use.  Only one usage of each address
                     is normally permitted.

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 errno(2)                                                           errno(2)

                     Cannot assign requested address.  Normally results from
                     an attempt to create a socket with an address not on
                     this machine.

      [EAFNOSUPPORT] Address family not supported by protocol family.  An
                     address incompatible with the requested protocol was
                     used.  For example, you should not necessarily expect
                     to be able to use PUP Internet addresses with ARPA
                     Internet protocols.

      [EAGAIN]       Resource temporarily unavailable.  This is likely a
                     temporary condition, and later calls to the same
                     routine may complete normally.

      [EALREADY]     Operation already in progress.  An operation was
                     attempted on a nonblocking object which already had an
                     operation in progress.

      [EBADF]        Bad file number.  Either a file descriptor refers to no
                     open file, a read (respectively write) request is made
                     to a file which is open only for writing (respectively
                     reading), or the file descriptor is not in the legal
                     range of file descriptors.

      [EBUSY]        Device or resource busy.  An attempt to mount a device
                     that was already mounted or an attempt was made to
                     dismount a device on which there is an active file
                     (open file, current directory, mounted-on file, active
                     text segment).  It will also occur if an attempt is
                     made to enable accounting when it is already enabled.
                     The device or resource is currently unavailable, such
                     as when a nonsharable device file is in use.

      [ECHILD]       No child processes.  A wait() was executed by a process
                     that had no existing or unwaited-for child processes.

      [ECONNABORTED] Software caused connection abort.  A connection abort
                     was caused internal to your host machine.

      [ECONNREFUSED] Connection refused.  No connection could be made
                     because the target machine actively refused it.  This
                     usually results from trying to connect to a service
                     that is inactive on the foreign host.

      [ECONNRESET]   Connection reset by peer.  A connection was forcibly
                     closed by a peer.  This normally results from the peer
                     executing a shutdown() call (see shutdown(2)).

      [EDEADLK]      Resource deadlock would occur.  A process which has
                     locked a system resource would have been put to sleep

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 errno(2)                                                           errno(2)

                     while attempting to access another process' locked

      [EDESTADDRREQ] Destination address required.  A required address was
                     omitted from an operation on a socket.

      [EDOM]         Math argument.  The argument of a function in the math
                     package (3M) is out of the domain of the function.

      [EEXIST]       File exists.  An existing file was mentioned in an
                     inappropriate context; e.g., link().

      [EFAULT]       Bad address.  The system encountered a hardware fault
                     in attempting to use an argument of a system call; can
                     also result from passing the wrong number of parameters
                     to a system call.  The reliable detection of this error
                     is implementation dependent.

      [EFBIG]        File too large.  The size of a file exceeded the
                     maximum file size (for the file system) or ULIMIT was
                     exceeded (see ulimit(2)), or a bad semaphore number in
                     a semop() call (see semop(2)).

      [EHOSTDOWN]    Host is down.  A socket operation encountered a dead
                     host.  Networking activity on the local host has not
                     been initiated.

      [EHOSTUNREACH] No route to host.  A socket operation was attempted to
                     an unreachable host.

      [EIDRM]        Identifier Removed.  This error is returned to
                     processes that resume execution due to the removal of
                     an identifier from the file system's name space (see
                     msgctl(2), semctl(2), and shmctl(2)).

      [EILSEQ]       Illegal byte sequence.  A wide character code has been
                     detected that does not correspond to a valid character,
                     or a byte sequence does not form a valid wide character

      [EINPROGRESS]  Operation now in progress.  An operation that takes a
                     long time to complete was attempted on a nonblocking
                     object (see ioct

      [EINTR]        Interrupted system call.  An asynchronous signal (such
                     as interrupt or quit), which the user has elected to
                     catch, occurred during a system call.  If execution is
                     resumed after processing the signal, it will appear as
                     if the interrupted system call returned this error
                     condition unless the system call is restarted (see

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 errno(2)                                                           errno(2)

      [EINVAL]       Invalid argument.  Some invalid argument (such as
                     unmounting a device that is not currently mounted,
                     mentioning an undefined signal in signal() or kill(),
                     or reading or writing a file for which lseek() has
                     generated a negative pointer).  Also set by the math
                     functions described in the (3M) entries of this manual.

      [EIO]          I/O error - some physical I/O error.  This error may in
                     some cases occur on a call following the one to which
                     it actually applies.

      [EISCONN]      Socket is already connected.  A connect() request was
                     made on an already connected socket, or, a sendto() or
                     sendmsg() request on a connected socket specified a
                     destination other than the connected party.

      [EISDIR]       Is a directory.  An attempt to open a directory for

      [ELOOP]        Too many levels of symbolic links were encountered
                     while resolving a path name.  See fs_symlinks(5) for
                     more information.

      [EMFILE]       Too many open files.  No process may have more than a
                     system-defined number of file descriptors open at a

      [EMLINK]       Too many links.  An attempt to make more than the
                     maximum number of links to a file.

      [EMSGSIZE]     Message too long.  The socket requires that the message
                     be sent atomically, and the size of the message to be
                     sent made this impossible.

      [ENAMETOOLONG] File name too long.  A path specified exceeds the
                     maximum path length for the system.  The maximum path
                     length is specified by PATH_MAX and is defined in
                     <limits.h>.  PATH_MAX is guaranteed to be at least 1023
                     bytes.  This error is also generated if the length of a
                     path name component exceeds NAME_MAX and the
                     _POSIX_NO_TRUNC option is in effect for the specified
                     path.  Currently, _POSIX_NO_TRUNC is in effect only for
                     HFS file systems configured to allow path name
                     components up to 255 bytes long (see convertfs(1M)) and
                     therefore only path names referring to such file
                     systems can generate the error for this case.  The
                     values of NAME_MAX, PATH_MAX, and _POSIX_NO_TRUNC for a
                     particular path name can be queried by using the
                     pathconf() system call (see pathconf(2)).

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 errno(2)                                                           errno(2)

      [ENETDOWN]     Network is down.  A socket operation encountered a dead

      [ENETRESET]    Network dropped connection on reset.  The host you were
                     connected to crashed and rebooted.

      [ENETUNREACH]  Network is unreachable.  A socket operation was
                     attempted to an unreachable network.

      [ENFILE]       File table overflow.  The system's table of open files
                     is full, and temporarily no more open()s can be

      [ENOBUFS]      No buffer space available.  An operation on a socket
                     was not performed because the system lacked sufficient
                     buffer space.

      [ENODEV]       No such device.  An attempt was made to apply an
                     inappropriate system call to a device (such as read a
                     write-only device).

      [ENOENT]       No such file or directory.  This error occurs when a
                     file name is specified and the file should exist but
                     does not, or when one of the directories in a path name
                     does not exist.  It also occurs with msgget(),
                     semget(), and shmget() when key does not refer to any
                     object and the IPC_CREAT flag is not set.

      [ENOEXEC]      Exec format error.  A request is made to execute a file
                     which, although it has the appropriate permissions,
                     does not start with a valid magic number (see
                     a.out(4)), or the file is too small to have a valid
                     executable file header.

      [ENOLCK]       System lock table is full.  Too many files have file
                     locks on them, or there are too many record locks on
                     files, or there are too many instances of a reading or
                     writing process sleeping until an enforcement mode lock
                     clears.  This error may also indicate system problems
                     in handling a lock request on a remote NFS file.  This
                     error is also currently returned for all attempts to
                     perform locking operations on a remote NFS file that
                     has its locking enforcement mode bit set, since the
                     stateless nature of NFS prevents maintaining the
                     necessary lock information.

      [ENOLINK]      No connection. The link with the device has been
                     severed or disconnected.

      [ENOMEM]       Not enough space.  During a system call such as exec(),
                     brk(), fork(), or sbrk(), a program asks for more space

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 errno(2)                                                           errno(2)

                     than the system is able to supply.  This may not be a
                     temporary condition; the maximum space size is a system
                     parameter.  The error can also occur if there is not
                     enough swap space during a fork().

      [ENOMSG]       No message of desired type.  An attempt was made to
                     receive a message of a type that does not exist on the
                     specified message queue; see msgop(2).

      [ENOPROTOOPT]  Protocol option not available.  This may be returned
                     for a getsockopt() or setsockopt() call (see
                     getsockopt(2)) if the user specified an option that the
                     local system does not support or for any system call
                     that causes the local system to send a network protocol
                     option that a remote system does not support, including
                     a system call that operates on an NFS file.

      [ENOSPC]       No space left on device.  During a write() to an
                     ordinary file, there is no free space left on the
                     device; or no space in system table during msgget(),
                     semget(), or semop() while SEM_UNDO flag is set.

      [ENOSYM]       Symbol does not exist in executable.  The dynamic
                     loader was unable to resolve a symbolic reference in a
                     shared library during a call to one of the dynamic
                     loader interface routines (see shl_load(3X).  The
                     program may be in an inconsistent state and should be
                     terminated immediately.

      [ENOSYS]       Function is not available.  The requested function or
                     operation is not implemented or not configured in the

      [ENOTBLK]      Block device required.  A nonblock file was mentioned
                     where a block device was required, such as in mount().

      [ENOTCONN]     Socket is not connected.  A request to send or receive
                     data was disallowed because the socket was not

      [ENOTDIR]      Not a directory.  A nondirectory was specified where a
                     directory is required, such as in a path prefix or as
                     an argument to chdir().

      [ENOTEMPTY]    Directory not empty.  An attempt was made to remove a
                     nonempty directory.

      [ENOTSOCK]     Socket operation on nonsocket.  An operation was
                     attempted on something that is not a socket.

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 errno(2)                                                           errno(2)

      [ENOTTY]       Not a typewriter.  The (ioctl()) command is
                     inappropriate to the selected device type.

      [ENXIO]        No such device or address. I/O on a special file refers
                     to a subdevice that does not exist, or is beyond the
                     limits of the device.  It can also occur when, for
                     example, a tape drive is not on line or no disk pack is
                     loaded on a drive.

      [EOPNOTSUPP]   Operation not supported.  The requested operation on a
                     socket or NFS file is either invalid or unsupported.
                     For example, this might occur when an attempt to
                     accept() a connection on a datagram socket fails.

      [EPERM]        Not owner.  Typically, this error indicates an attempt
                     to modify a file in some way forbidden except to its
                     owner or the superuser, such as to change its mode.  It
                     is also returned for attempts by ordinary users to do
                     things for which they need, but lack, a special

      [EPFNOSUPPORT] Protocol family not supported.  The protocol family has
                     not been configured into the system or no
                     implementation for it exists.  The socket is not

      [EPIPE]        Broken pipe.  Data has been written to a pipe for which
                     the other (reading) end has been closed.  This most
                     often occurs when the reading process exits before the
                     writing process.  This condition also generates the
                     signal SIGPIPE; the error is returned if the signal is

                     Protocol not supported.  The protocol has not been
                     configured into the system or no implementation for it

      [EPROTOTYPE]   Protocol wrong type for socket.  A protocol was
                     specified that does not support the semantics of the
                     socket type requested.  For example, ARPA Internet UDP
                     protocol cannot be used with type SOCK_STREAM.

      [ERANGE]       Result too large.  The value of a function in the math
                     package (3M) is not representable within machine
                     precision, or a semop() call would cause either a
                     semaphore value or a semaphore adjust value to exceed
                     it system-imposed maximum.

      [EROFS]        Read-only file system.  An attempt to modify a file or
                     directory was made on a device mounted read-only.

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 errno(2)                                                           errno(2)

      [ESHUTDOWN]    Cannot send after socket shutdown.  A request to send
                     data was disallowed because the socket had already been
                     shut down with a previous shutdown() call.

                     Socket type not supported.  The support for the socket
                     type has not been configured into the system or no
                     implementation for it exists.

      [ESPIPE]       Illegal seek.  An lseek() was issued to a pipe.

      [ESRCH]        No such process.  No process can be found corresponding
                     to that specified by pid in kill(), rtprio(), or
                     ptrace(), or the process is not accessible.

      [ETIMEDOUT]    Connection timed out.  A connect() request failed
                     because the connected party did not properly respond
                     after a period of time (timeout period varies,
                     depending on the communication protocol).

      [ETXTBSY]      Text file busy.  An attempt to execute an executable
                     file which is currently open for writing (or reading).
                     Also, an attempt to open for writing an otherwise
                     writable file which is currently open for execution.

      [EWOULDBLOCK]  Operation would block.  An operation which would cause
                     a process to block was attempted on an object in
                     nonblocking mode (see ioct

      [EXDEV]        Cross-device link.  A link to a file on another device
                     was attempted.

 DEPENDENCIES    [Toc]    [Back]
      The following NFS errors are also defined:

           [EREFUSED]     The same error as [ECONNREFUSED].  The external
                          variable errno is defined as [ECONNREFUSED] for
                          NFS compatibility.

           [EREMOTE]      Too many levels of remote in path.  An attempt was
                          made to remotely mount an NFS file system into a
                          path which already has a remotely mounted NFS file
                          system component.

           [ESTALE]       Stale NFS file handle.  A client referenced an
                          open file, but the file was previously deleted.

      errno: AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI

 Hewlett-Packard Company            - 8 -   HP-UX 11i Version 2: August 2003
[ Back ]
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