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write(9e) [opensolaris man page]

write(9E)							Driver Entry Points							 write(9E)

write - write data to a device SYNOPSIS
#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); INTERFACE LEVEL
Architecture independent level 1 (DDI/DKI). This entry point is optional. PARAMETERS
dev Device number. uio_p Pointer to the uio(9S) structure that describes where the data is to be stored in user space. cred_p Pointer to the user credential structure for the I/O transaction. DESCRIPTION
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 per- tinent. RETURN VALUES
The write() routine should return 0 for success, or the appropriate error number. EXAMPLES
The following is an example of a write() routine using physio(9F) to perform writes to a seekable device: 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)); } SEE ALSO
read(2), write(2), read(9E), physio(9F), cb_ops(9S), uio(9S) Writing Device Drivers SunOS 5.11 28 Mar 1997 write(9E)

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awrite(9E)							Driver Entry Points							awrite(9E)

awrite - asynchronous write to a device SYNOPSIS
#include <sys/uio.h> #include <sys/aio_req.h> #include <sys/cred.h> #include <sys/ddi.h> #include <sys/sunddi.h> intprefixawrite(dev_t dev, struct aio_req *aio_reqp, cred_t *cred_p); INTERFACE LEVEL
Solaris DDI specific (Solaris DDI). This entry point is optional. Drivers that do not support an awrite() entry point should use nodev(9F) PARAMETERS
dev Device number. aio_reqp Pointer to the aio_req(9S) structure that describes where the data is stored. cred_p Pointer to the credential structure. DESCRIPTION
The driver's awrite() routine is called to perform an asynchronous write. getminor(9F) can be used to access the minor number component of the dev argument. awrite() may use the credential structure pointed to by cred_p to check for superuser access by calling drv_priv(9F). The awrite() routine may also examine the uio(9S) structure through the aio_req structure pointer, aio_reqp. awrite() must call aphysio(9F) with the aio_req pointer and a pointer to the driver's strategy(9E) routine. No fields of the uio(9S) structure pointed to by aio_req, other than uio_offset or uio_loffset, may be modified for non-seekable devices. RETURN VALUES
The awrite() routine should return 0 for success, or the appropriate error number. CONTEXT
This function is called from user context only. EXAMPLES
Example 1: Using the awrite routine: The following is an example of an awrite() routine: static int xxawrite(dev_t dev, struct aio_req *aio, cred_t *cred_p) { int instance; struct xxstate *xsp; instance = getminor(dev); xsp = ddi_get_soft_state(statep, instance); /*Verify soft state structure has been allocated */ if (xsp == NULL) return (ENXIO); return (aphysio(xxstrategy, anocancel, dev, B_WRITE, xxminphys, aio)); } SEE ALSO
write(2), aiowrite(3AIO), aread(9E), read(9E), strategy(9E), write(9E), anocancel(9F), aphysio(9F), ddi_get_soft_state(9F), drv_priv(9F), getminor(9F), minphys(9F), nodev(9F), aio_req(9S), cb_ops(9S), uio(9S) Writing Device Drivers BUGS
There is no way other than calling aphysio(9F) to accomplish an asynchronous write. SunOS 5.10 28 Mar 1997 awrite(9E)

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