GB_STREAM_DESC
struct GB_STREAM;
typedef
struct {
int (*
open)(struct GB_STREAM *stream, const char *path, int mode, void *data);
int (*
close)(struct GB_STREAM *stream);
int (*
read)(struct GB_STREAM *stream, char *buffer, long len);
int (*
write)(struct GB_STREAM *stream, char *buffer, long len);
int (*
seek)(struct GB_STREAM *stream, long long pos, int whence);
int (*
tell)(struct GB_STREAM *stream, long long *pos);
int (*
flush)(struct GB_STREAM *stream);
int (*
eof)(struct GB_STREAM *stream);
int (*
lof)(struct GB_STREAM *stream, long long *len);
int (*
handle)(struct GB_STREAM *stream);
}
GB_STREAM_DESC;
This describe is a function pointer table that must point at the implementation functions
of a stream.
Each stream has a pointer to such a structure. See
GB_STREAM for more details.
|
Function
|
What should be done
|
What should be returned
|
|---|
open
|
Opens the stream.
This function is never called directly by the interpreter, as you must open
the file yourself, by instanciating the Stream Gambas object, and by filling the GB_STREAM
structure appropriately.
|
TRUE if the stream cannot be opened, and FALSE if everything is OK.
|
close
|
Closes the stream.
|
FALSE.
|
read
|
Reads len bytes into the stream, and fills the buffer with them.
|
TRUE if there was an error, and FALSE if everything is OK.
The errno code is used by the interpreter
to choose the error message.
|
write
|
Writes the len bytes located at buffer to the stream.
|
TRUE if there was an error, and FALSE if everything is OK.
The errno code is used by the interpreter
to choose the error message.
|
seek
|
Seeks into the stream.
-
pos is the position inside the stream.
-
whence is one the following constants:
-
SEEK_SET, to indicate that pos is an absolute position.
-
SEEK_CUR, to indicate that pos is an offset to the current position.
-
SEEK_END, to indicate that pos is an offset from the end of the stream.
|
TRUE if seeking is impossible, and FALSE if everything is OK.
|
tell
|
Returns the current stream position in pos.
|
TRUE if seeking is impossible, and FALSE if everything is OK.
|
flush
|
Flushes the stream.
|
TRUE if there was an error, and FALSE if everything is OK.
If flushing has no sense for your stream, then you must return FALSE.
|
eof
|
Checks the end of the stream.
|
TRUE if the end of the stream is reached, FALSE otherwise.
|
lof
|
Returns in len the length of the stream.
If this has no sense for your stream, and if the handle function returns a
system file descriptor, you can let the interpreter returns the maximum number
of bytes that can be read on the stream for you, by putting 0 in len.
|
FALSE.
|
handle
|
Returns the underlying system file descriptor.
|
The underlying system file descriptor.
|
See also