sopen()                 Open a File for Shared Operations

 #include   <io.h>

 sopen(path, access, shflag, mode)
 char *path;    Pathname.
 int access;    Access value.
 int shrflag;   Share flag.
 int mode;      Mode of opening.

        sopen() opens a file for shared reading and writing. All parameters
        -- path, access, and mode, are the same as in open(). The share
        flag shrflag is a combination of these values:

                SH_COMPAT       Compatibilty mode
                SH_DENYRW       Deny read/write access
                SH_DENYWR       Deny write access
                SH_DENYRD       Deny read access
                SH_DENYNONE     Allows read/write access
                SH_DENYNO       Allows read/write access

        See open() for more information and examples.

       Returns:     A nonegative file handle if successful. If the
                    return value is negative, the global value errno is
                    set to:
                                ENOENT          Path not found
                                EMFILE          Too many open files
                                EACCES          Permission denied
                                EINVACC         Invalid access code