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Section 8.10.2.1:
FILE_MODES
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Formal Types
types
SAME = FILE_MODES ;
FILE_MODES = token
This class implements the concept of the kind of connection between a file
class object and the underlying file in the program environment, indicating
the actions to which the connection is limited.
The corresponding names in the culture-dependent resources file should be
the language-dependent names for the English notions corresponding to the
enumeration values defined below.
External specifications
The following feature is required to be implemented for this
class in accordance with the specification given in $IS_EQ :-
The following feature is required to be implemented for this class in
accordance with the specification given in $HASH :-
The following features are required to be implemented for this class in
accordance with the specifications given in $BINARY :-
The following featuress are required to be implemented for this class in
accordance with the specifications given in $STR :-
The following features are required to be implemented for this class in
accordance with the specification given in $INSTR :-
The following features are required to be implemented for this class in
accordance with the specifications given in $ANCHORED_FMT :-
The following features are required to be implemented for this class in
accordance with the specifications given in $ENUMS{T} :-
Enumeration Values
This enumeration provides the values which indicate the
permitted actions in respect of the file created/opened with that particular
mode :-
- Write_Text - Either an existing file is to be
opened or a new file is to be created with the file cursor positioned at
the beginning for writing text data only irrespective of the encoding in
use. When the file is closed its length will be given by the last
position written. Seeking to a particular position in the file is not
permitted.
- Write_Binary - Either an existing file is to be
opened or a new file is to be created with the file cursor positioned at
the beginning for writing binary data only. When the file is closed its
length will be given by the last position written. Seeking to a
particular position in the file is not permitted.
- Read_Text - An existing file is to be opened with
the file cursor positioned at the beginning for reading text data only
irrespective of the encoding used. The file may not be written to.
Seeking to a particular position in the file is permitted.
- Read_Binary - An existing file is to be opened
with the file cursor positioned at the beginning for reading binary data
only. The file may not be written to. Seeking to a particular position
in the file is permitted.
- Append_Text - An existing file is to be opened
with the file cursor positioned at the end for writing text data only
irrespective of the encoding in use. When the file is closed its length
will be given by the last position written. Seeking to a particular
position in the file is not permitted.
- Append_Binary - An existing file is to be opened
with the file cursor positioned at the end for writing binary data only.
When the file is closed its length will be given by the last position
written. Seeking to a particular position in the file is not
permitted.
- Create_Upd_Text - A new file is to be created with
the file cursor positioned at the end for writing text data only
irrespective of the encoding in use. It is an error if the file already
exists. Reading and seeking to a position in the file are permitted.
- Create_Upd_Binary - A new file is to be created
with the file cursor positioned at the end for writing binary data only.
It is an error if the file already exists. Reading and seeking to a
position in the file are permitted.
- Update_Text - An existing file is to be opened
with the file cursor positioned at the beginning for reading and writing
text data only irrespective of the encoding used. Seeking to a particular
position in the file is permitted.
- Update_Binary - An existing file is to be opened
with the file cursor positioned at the beginning for reading and writing
binary data. Seeking to a particular position in the file is
permitted.
- App_Upd_Text - An existing file is to be opened
with the file cursor positioned at the end for writing text data only
irrespective of the encoding used. Reading and seeking to a particular
position in the file are permitted.
- App_Upd_Binary - An existing file is to be opened
with the file cursor positioned at the end for writing binary data.
Reading and seeking to a particular position in the file are
permitted.
Comments
or enquiries should be made toKeith Hopper.
Page last modified: Wednesday, 4 April 2001.
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