Provides a means of transmitting data to the token-ring device handler.
|devno||Specifies major and minor device numbers.|
|uiop||Points to a uio structure specifying the location and length of the caller's data.|
|chan||Specifies the channel number assigned by the tokmpx entry point.|
|arg||Points to a write_extension structure. If the arg parameter is null, then default values are assumed.|
The tokwrite entry point provides the means for transmitting data to the token-ring device handler. The kernel calls it when a user-mode caller issues a write, writex, writev, or a writevx subroutine.
For a user-mode process, the kernel fills in the uio structure with the appropriate values. A kernel-mode process must fill in the uio structure as described by the ddwrite communications entry point.
For the tokwrite entry point, the arg parameter may point to a write_extension structure. This structure is defined in the /usr/include/sys/comio.h file and contains the following fields:
|status||Indicates the status condition that occurred. Possible values for the returned status field are:|
|flag|| Consists of a possible bitwise OR one of the following:
|write_id||For a user-mode caller, the write_id field is returned to the caller by the CIO_GET_STAT operation (if the CIO_ACK_TX_DONE option is selected). For a kernel-mode caller, the write_id field is returned to the caller by the stat_fn function that was provided at open time.|
The tokwrite entry point can be called from the process environment only.
|EAGAIN||Indicates the transmit queue is full.|
|EFAULT||Indicates an invalid address was supplied.|
|EINTR||Indicates a system call was interrupted.|
|EINVAL||Indicates the specified parameter is not valid.|
|ENETDOWN||Indicates the network is down. The device is unable to process the write.|
|ENETUNREACH||Indicates the device is in network Recovery mode and unable to process the entry point.|
|ENOCONNECT||Indicates the device has not been started.|
|ENOMEM||Indicates the device handler was unable to allocate the required memory.|
|ENXIO||Indicates the specified minor number is not valid.|
The tokwrite entry point functions with a Token-Ring High Performance Network Adapter that has been correctly configured for use on a qualified network. Consult adapter specifications for more information on configuring the adapter and network qualifications.
The CIO_GET_FASTWRT tokioctl entry point
The ddwrite entry point, tokfastwrt entry point, tokmpx entry point, tokopen entry point.
The write, writex, writev, or writevx,subroutine.
The CIO_START tokioctl operation.
The uio structure in BkSym.TRKernel5;.
See the Use of mbuf Structures in the Communications PDH in AIX Kernel Extensions and Device Support Programming Concepts for more information about mbuf structures.