FILE_HANDLERS(STHREAD )

Shore Programmer's Manual - 2 August 96

NAME

SYNOPSIS

#include <sthread.h>

class sfile_hdl_base_t : public w_vbase_t {
public:
    enum { rd = 1, wr = 2, ex = 4 };
    enum { max = 64 };

    NORET			sfile_hdl_base_t(
	int			    fd,
	int			    mask);
    NORET			~sfile_hdl_base_t();

    const int			fd;

    virtual void		read_ready() = 0;
    virtual void 		write_ready() = 0;
    virtual void 		expt_ready() = 0;

    void			enable();
    void			disable();

    static w_rc_t		wait(long timeout = sthread_base_t::WAIT_FOREVER);
    static void			dump(const char* str, ostream& out);

    static bool			is_active(int fd);
};

class sfile_read_hdl_t : public sfile_hdl_base_t {
public:
    NORET			sfile_read_hdl_t(int fd);
    NORET			~sfile_read_hdl_t();

    w_rc_t			wait(long timeout);
    void			shutdown();
    bool			is_down()  { return _shutdown; }
protected:
    // hide base::read_ready
    virtual void		read_ready();
};

class sfile_write_hdl_t : public sfile_hdl_base_t {
public:
    NORET			sfile_write_hdl_t(int fd);
    NORET			~sfile_write_hdl_t();

    w_rc_t			wait(long timeout);
    void			shutdown();
    bool			is_down()  { return _shutdown; }
protected:
    // hide base::write_ready
    virtual void		write_ready();
};

DESCRIPTION

Class sfile_hdl_base_t

sfile_hdl_base_t(fd, mask)

The constructor creates a file handler for the file descriptor fd. Parameter mask is a bitwise ORed value of the following flags:

	rd	signifying read intention
	wr 	signifying write intention
	ex	signifying exception intention

~sfile_hdl_base_t()

enable()

The enable method enables the file handler to be waited on when the thread package calls the select system call.

disable()

The disable method disables the file handler from being waited on when the thread package calls the select system call.

wait()

The wait method waits for some file handlers to be ready. An error is returned if timeout milliseconds elapsed before any file handler is ready. Warning: this method blocks the entire process on a unix select system call.

is_active(fd)

The is_active method returns true if a file handler exists for file descriptor fd.

Class sfile_read_hdl_t

sfile_read_hdl_t(fd)

The constructor creates a read-intention file handler on file descriptor fd.

~sfile_read_hdl_t()

shutdown()

The shutdown method turns off monitoring of the file descriptor manages by the file handler. Any threads is waiting on it, awakened with a stBADFILEHDL error code.

wait()

The wait method suspends the current thread, waiting to read from the file descriptor. The method returns timeout error if timeout milliseconds elapse before anything arrives on the file descriptor.

Class sfile_write_hdl_t

This class has only recently been implemented. No documentation is available yet. TODO

ERRORS

EXAMPLES

    stdin_thread_t::run()
    {
	sfile_read_hdl_t h(0);    // handle on stdin
	char buf[256];
	for (;;)  {
	    if (h.wait())  {
		/* handle error */
		...
	    }
	    /* stdin is ready -- read user command into buf */
	    read(0, buf, sizeof(buf)-1);
	    /* process user command */
	    ...
	}
    }

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