Provides the means for receiving data from the token-ring device handler.
| devno | Specifies major and minor device numbers. |
| uiop | Points to a uio structure. For a calling user-mode process, the uio structure specifies the location and length of the caller's data area in which to transfer information. The kernel fills in the uio structure for the user. |
| chan | Specifies the channel number assigned by the tokmpx entry point. |
| arg | Can be null or points to the read_extension structure. This structure is defined in the /usr/include/sys/comio.h file. |
Note: Only user-mode callers should use the tokread entry point.
The tokread entry point provides the means for receiving data from the token-ring device handler. When a user-mode caller issues a read, readx, readv, or readvx subroutine, the kernel calls the tokread entry point.
For this operation, the arg parameter may point to the read_extension structure. This structure is defined in the /usr/include/sys/comio.h file and contains the following fields:
| status | Contains additional information about the completion of the tokread entry point. Possible values for this field are: |
| netid | Not used |
| sessid | Not used |
The tokread entry point can be called from the process environment only.
| EACCES | Indicates an illegal call from a kernel-mode user. |
| ENXIO | Indicates the specified minor number is not valid. |
| EINTR | Indicates a system call was interrupted. |
| EMSGSIZE | Indicates the data was too large to fit into the receive buffer and that no arg parameter was supplied to provide an alternate means of reporting this error with a status of CIO_BUF_OVFLW. |
| EFAULT | Indicates that the supplied address is not valid. |
| ENOCONNECT | Indicates the device has not been started. |
The tokread 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 read, readx, readv, or readvx subroutine.
The tokmpx entry point, tokwrite entry point.
Common Communications Status and Exception Codes in AIX Kernel Extensions and Device Support Programming Concepts.