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| Driver Entry Points | write(9E) |
| | write - write data to a device |
SYNOPSIS
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#include <sys/types.h>
#include <sys/errno.h>
#include <sys/open.h>
#include <sys/cred.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
int prefixwrite(dev_t dev, struct uio *uio_p, cred_t *cred_p); |
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Architecture independent level 1 (DDI/DKI). This entry point is optional.
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dev
- Device number.
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uio_p
- Pointer to the uio(9S) structure that describes where the data is to be stored in user space.
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cred_p
- Pointer to the user credential structure for the I/O transaction.
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Used for character or raw data I/O, the driver write() routine is called indirectly through cb_ops(9S) by the write(2) system call. The write() routine supervises the data transfer from user space to a device described by the uio(9S) structure.
The write() routine should check the validity of the minor number component of dev and the user credentials pointed to by cred_p,
if pertinent.
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The write() routine should return 0 for success, or the appropriate error number.
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| | Example 1.
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The following is an example of a write() routine using physio(9F) to perform writes to a seekable device:
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static int
xxwrite(dev_t dev, struct uio *uiop, cred_t *credp)
{
int instance;
xx_t xx;
instance = getminor(dev);
xx = ddi_get_soft_state(xxstate, instance);
if (xx == NULL)
return (ENXIO);
return (physio(xxstrategy, NULL, dev, B_WRITE,
xxmin, uiop));
}
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