null(7)
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null Special File
the null file
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DESCRIPTION
The null pseudo-device is the proverbial "bit bucket". It works
just as an ordinary disk file except that there is never any data
to read, and written data is discarded.
For the open and close system calls, user visible functionality
is the same as for an ordinary disk file.
For the read system call, user visible functionality is the same
as for an ordinary disk file, except that the read will always
return 0 bytes and the user's buffer will be unmodified.
For the write system call, user visible functionality is the same
as for an ordinary disk file, except that the data is discarded.
There are no ioctl system calls that are specific to null. Other
ioctl calls that apply to ordinary disk files also apply to null.
Select always returns READY for both read and write operations.
FILES
/dev/null
DG/UX 4.00 Page 1
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