copyout(9f) [sunos man page]

copyout(9F)						   Kernel Functions for Drivers 					       copyout(9F)

NAME

       copyout - copy data from a driver to a user program

SYNOPSIS

       #include <sys/types.h>
       #include <sys/ddi.h>

       int copyout(const void *driverbuf, void *userbuf, size_t cn);

INTERFACE LEVEL

       This interface is obsolete. ddi_copyout(9F) should be used instead.

PARAMETERS

       driverbuf       Source address in the driver from which the data is transferred.

       userbuf	       Destination address in the user program to which the data is transferred.

       cn	       Number of bytes moved.

DESCRIPTION

       copyout() copies data from driver buffers to user data space.

       Addresses  that	are  word-aligned  are	moved most efficiently.  However, the driver developer is not obligated to ensure alignment.  This
       function automatically finds the most efficient move algorithm according to address alignment.

RETURN VALUES

       Under normal conditions, a 0 is returned to indicate a successful copy.	Otherwise, a -1 is returned if one of the following occurs:

	 o  Paging fault; the driver tried to access a page of memory for which it did not have read or write access.

	 o  Invalid user address, such as a user area or stack area.

	 o  Invalid address that would have resulted in data being copied into the user block.

	 o  Hardware fault; a hardware error prevented access to the specified user memory. For example, an  uncorrectable  parity  or	ECC  error
	    occurred.

       If a -1 is returned to the caller, driver entry point routines should return EFAULT.

CONTEXT

       copyout() can be called from user context only.

EXAMPLES

       Example 1: An ioctl() Routine

       A  driver ioctl(9E) routine (line 10) can be used to get or set device attributes or registers.	In the XX_GETREGS condition (line 17), the
       driver copies the current device register values to a user data area (line 18).	If the specified argument contains an invalid address,	an
       error code is returned.

	1  struct device  {	 /* layout of physical device registers  */
	2	int	 control;     /* physical device control word  */
	3	int	 status;      /* physical device status word   */
	4	short	 recv_char;   /* receive character from device */
	5	short	 xmit_char;   /* transmit character to device  */
	6  };
	7
	8  extern struct device xx_addr[]; /* phys. device regs. location */
	9    . . .
       10  xx_ioctl(dev_t dev, int cmd, int arg, int mode,
       11      cred_t *cred_p, int *rval_p)
       12		...
       13  {
       14      register struct device *rp = &xx_addr[getminor(dev) >> 4];
       15      switch (cmd) {
       16
       17      case XX_GETREGS:     /* copy device regs. to user program */
       18	     if (copyout(rp, arg, sizeof(struct device)))
       19		 return(EFAULT);
       20	     break;
       21		...
       22      }
       23		...
       24  }

ATTRIBUTES

       See attributes(5) for a description of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Stability Level 	     |Obsolete			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       attributes(5), ioctl(9E), bcopy(9F), copyin(9F), ddi_copyin(9F), ddi_copyout(9F), uiomove(9F)

       Writing Device Drivers

NOTES

       Driver writers who intend to support layered ioctls in their ioctl(9E) routines should use ddi_copyout(9F) instead.

       Driver defined locks should not be held across calls to this function.

       copyout() should not be used from a streams driver. See M_COPYIN and M_COPYOUT in STREAMS Programming Guide.

SunOS 5.10							    27 Sep 2002 						       copyout(9F)