8. Function specifications-4

8.4 Immediate return type read

List

Title Function specifications

Function Start reading data

Function Name GFS_NwFread

No 4.1

Form

Sint32 GFS_NwFread (GfsHn gfs, Sint32 nsct, void * buf, Sint32 bsize)

input

gfs	: File handle
nsct	: Number of sectors to read
bsize	: Size of read area (unit: number of bytes)

output

buf: Read area

Function value

Error code.

function

Issue a data read request to the server function. When the requested access operation is complete, the access pointer advances the nsct sector.

remarks

As for the address boundary of buf, the same precautions as the remarks of GFS_Fread are required.

List

Title Function specifications

Function Start look-ahead to CD buffer

Function Name GFS_NwCdRead

No 4.2

Form

Sint32 GFS_NwCdRead (GfsHn gfs, Sint32 nsct)

input

gfs	: File handle
nsct	: Number of sectors to read

output

none

Function value

Error code.

function

Issue a read-ahead request to the data CD buffer for the server function.
The access pointer does not change when the requested read process is completed. If the following conditions are not met, the access operation for the specified file handle will not be completed.

• The data in the nsct sector is transferred to the host area by the GFS_Fread function or the GFS_NwFread function.
• The access operation is stopped by the GFS_NwStop function.

remarks

To check that the transfer to the host area by the GFS_NwFread function after the start of read-ahead is completed, perform the following processing.

• Get the number of bytes transferred with GFS_NwGetStat.
• Check if the number of transferred bytes is equal to the desired number of bytes.
  (If it is equal to the target number of bytes, the transfer is complete.)

Note that if you read ahead with the GFS_NwCdRead function, you cannot check the completion of the GFS_NwFread function with the GFS_NwIsComplete function.

List

Title Function specifications

Function Checking the completion of access operation

Function Name GFS_NwIsComplete

No 4.3

Form

Bool GFS_NwIsComplete (GfsHn gfs)

input

gfs: file handle

output

none

Function value

Access operation status.

function

Check if the access operation of the server function is completed. Function values have the following meanings:

TRUE	: Access completed
FALSE	:in action

List

Title Function specifications

Function Stop access operation

Function Name GFS_NwStop

No 4.4

Form

Sint32 GFS_NwStop (GfsHn gfs)

input

gfs: file handle

output

none

Function value

Access pointer at the time of cancellation. Negative error code in case of error.

function

Cancels the access operation of the server function. GFS_NwExecServer continues to access the following files:

List

Title Function specifications

Function Get current access status

Function Name GFS_NwGetStat

No 4.5

Form

void GFS_NwGetStat (GfsHn gfs, Sint32 * stat, Sint32 * ndata)

input

gfs: File handle

output

stat	: Current access status
ndata	:The number of data

Function value

none

function

It is used to get the access status of the server function.
The meaning of the data for each access status is shown below.

Access status	process	Meaning of the number of data
GFS_NWSTAT_NOACT	none	No meaning
GFS_NWSTAT_FREAD	Reading from CD to host area	Number of bytes read into host area
GFS_NWSTAT_CDREAD	Look-ahead to CD buffer	Number of sectors read into the CD buffer

List

Title Function specifications

Function Execution of access operation on a file-by-file basis

Function Name GFS_NwExecOne

No 4.6

Form

Sint32 GFS_NwExecOne (GfsHn gfs)

input

gfs: file handle

output

none

Function value

Execution state (GFS_SVR_ ~). Negative error code in case of error.

function

Access server function for a single file. The following processing is executed according to the access operation called immediately before for the file handle.

• GFS_NwFread
  Performs read processing to the CD buffer and transfer processing to the host.
• GFS_NwCdRead
  Reads into the CD buffer.

List

Title Function specifications

Function Performing multiple file access actions

Function Name GFS_NwExecServer

No 4.7

Form

Sint32GFS_NwExecServer (GfsHn * now_gfs)

input

none

output

now_gfs: File handle to be executed

Function value

Access server status (GFS_SVR_ ~). Negative error code in case of error.

function

Access server function for multiple files. Performs actual access (GFS_NwExecOne) in the order in which the requests are issued.
After the access operation of one file is completed, the next process is started.
When the processing of multiple files is completed, it becomes GFS_SVR_COMPLETED.