sdget(2)       UNIX System V(Application Compatibility Package)        sdget(2)


NAME
      sdget, sdfree - attach and detach a shared data segment

SYNOPSIS
      cc [flag . . .] file . . . -lx
      #include <sys/sd.h>

      char *sdget(char *path, int flags, /* long size, int mode */);

      int sdfree(char *addr);

DESCRIPTION
      sdget attaches a shared data segment to the data space of the current
      process.  The actions performed are controlled by the value of flags.
      flags values are constructed by an OR of flags from the following list:

      SDRDONLY   Attach the segment for reading only.

      SDWRITE    Attach the segment for both reading and writing.

      SDCREAT    If the segment named by path exists and is not in use
                  (active), this flag will have the same effect as creating a
                  segment from scratch.  Otherwise, the segment is created
                  according to the values of size and mode.  Read and write
                  access to the segment is granted to other processes based on
                  the permissions passed in mode, and functions the same as
                  those for regular files.  Execute permission is meaningless.
                  The segment is initialized to contain all zeroes.

      SDUNLOCK   If the segment is created because of this call, the segment
                  will be made so that more than one process can be between
                  sdenter and sdleave calls.

      sdfree detaches the current process from the shared data segment that is
      attached at the specified address.  If the current process has done
      sdenter but not an sdleave for the specified segment, sdleave will be
      done before detaching the segment.

      When no process remains attached to the segment, the contents of that
      segment disappear, and no process can attach to the segment without
      creating it by using the SDCREAT flag in sdget.  errno is set to EEXIST
      if a process tries to create a shared data segment that exists and is in
      use.  errno is set to ENOTNAM if a process attempts an sdget on a file
      that exists but is not a shared data type.

DIAGNOSTICS
      On successful completion, the address at which the segment was attached
      is returned.  Otherwise, -1 is returned, and errno is set to indicate the
      error.  errno is set to EINVAL if a process does an sdget on a shared
      data segment to which it is already attached.  errno is set to EEXIST if
      a process tries to create a shared data segment that exists an is in use.
      errno is set to ENOTNAM if a process attempts an sdget on a file that


10/89                                                                    Page 1

sdget(2)       UNIX System V(Application Compatibility Package)        sdget(2)


      exists but is not a shared data type.

      The mode parameter must be included on the first call of the sdget
      function.

SEE ALSO
      sdenter(2), sdgetv(2)















































Page 2                                                                    10/89