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.

GB_STREAM_DESC

See also