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Q66129: Use of the shflag with sopen()

Article: Q66129
Product(s): See article
Version(s): 6.00
Operating System(s): MS-DOS
Keyword(s): ENDUSER | S_QUICKC | mspl13_c
Last Modified: 17-OCT-1990

The shflag used with the sopen() function can be one of five manifest
constants (defined in FCNTL.H). The following lists the constants and
their uses:

SH_COMPAT   Sets compatibility mode. Other programs can open the file
            and perform read or write operations as long as no process
            specifies any sharing mode other than compatibility mode.
            This is the sharing mode used in the open function under
            MS-DOS. This sharing code is not available under OS/2.

SH_DENYRW   Deny all. Other programs cannot open the file.

SH_DENYWR   Deny write. Other programs cannot open the file in
            compatibility mode or with write access.

SH_DENYRD   Deny read. Other program cannot open the file in
            compatibility mode or with read access.

SH_DENYNO   Deny none. Other programs can open the file and perform
            both read and write operations but cannot open the file in
            compatibility mode. This is the sharing mode used in the
            open function under OS/2.

In a network environment under MS-DOS, it is recommended that the
SH_COMPAT mode be used if the file is to be shared for reading and
writing. For further information about file modes, see the "MS-DOS
Encyclopedia," Article 7, "File and Record Management".

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