Cartridge Services — File I/O Interface

Table 20-5 lists the file I/O interface functions that are described in this section.

Table 20-5 File I/O Interface Functions

Function Purpose

"OCIFileClose()"

Close a previously opened file

"OCIFileExists()"

Test to see if the file exists

"OCIFileFlush()"

Write buffered data to a file

"OCIFileGetLength()"

Get the length of a file

"OCIFileInit()"

Initialize the OCIFile package

"OCIFileOpen()"

Open a file

"OCIFileRead()"

Read from a file into a buffer

"OCIFileSeek()"

Change the current position in a file

"OCIFileTerm()"

Terminate the OCIFile package

"OCIFileWrite()"

Write buflen bytes into the file

See Also:

Oracle Database Data Cartridge Developer's Guide for more information about using these functions

OCIFileObject

The OCIFileObject data structure holds information about the way in which a file should be opened and the way in which it is accessed after it has been opened. When this structure is initialized by OCIFileOpen(), it becomes an identifier through which operations can be performed on that file. It is a necessary parameter to every function that operates on open files. This data structure is opaque to OCIFile clients. It is initialized by OCIFileOpen() and terminated by OCIFileClose().

OCIFileClose()

Purpose

Closes a previously opened file.

Syntax

sword OCIFileClose( void          *hndl, 
                    OCIError      *err, 
                    OCIFileObject *filep );

Parameters

hndl (IN)

The OCI environment or user session handle.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

filep (IN/OUT)

A pointer to a file identifier to be closed.

Comments

Once this function returns OCI_SUCCESS, the OCIFileObject structure pointed to by filep is destroyed. Therefore, you should not attempt to access this structure after this function returns OCI_SUCCESS.

Returns

OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

OCIFileExists()

Purpose

Tests to see if the file exists.

Syntax

sword OCIFileExists( void     *hndl, 
                     OCIError *err, 
                     OraText  *filename, 
                     OraText  *path, 
                     ub1      *flag );

Parameters

hndl (IN)

The OCI environment or user session handle.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

filename (IN)

The file name as a NULL-terminated string.

path (IN)

The path of the file as a NULL-terminated string.

flag (OUT)

Set to TRUE if the file exists or FALSE if it does not.

Returns

OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

OCIFileFlush()

Purpose

Writes buffered data to a file.

Syntax

sword OCIFileFlush( void          *hndl
                    OCIError      *err, 
                    OCIFileObject *filep );

Parameters

hndl (IN)

The OCI environment or user session handle.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

filep (IN/OUT)

A file identifier that uniquely references the file.

Returns

OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

OCIFileGetLength()

Purpose

Gets the length of a file.

Syntax

sword OCIFileGetLength( void     *hndl, 
                        OCIError *err, 
                        OraText  *filename, 
                        OraText  *path, 
                        ubig_ora *lenp );

Parameters

hndl (IN)

The OCI environment or user session handle.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

filename (IN)

The file name as a NULL-terminated string.

path (IN)

The path of the file as a NULL-terminated string.

lenp (OUT)

Set to the length of the file in bytes.

Returns

OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

OCIFileInit()

Purpose

Initializes the OCIFile package. It must be called before any other OCIFile routine is called.

Syntax

sword OCIFileInit( void     *hndl, 
                   OCIError *err );

Parameters

hndl (IN)

The OCI environment or user session handle.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

Returns

OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

OCIFileOpen()

Purpose

Opens a file.

Syntax

sword OCIFileOpen( void           *hndl, 
                   OCIError       *err, 
                   OCIFileObject  **filep, 
                   OraText        *filename, 
                   OraText        *path, 
                   ub4            mode, 
                   ub4            create, 
                   ub4            type );

Parameters

hndl (IN)

The OCI environment or user session handle.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

filep (IN/OUT)

The file identifier.

filename (IN)

The file name as a NULL-terminated string.

path (IN)

The path of the file as a NULL-terminated string.

mode (IN)

The mode in which to open the file. Valid modes are

OCI_FILE_READ_ONLY

OCI_FILE_WRITE_ONLY

OCI_FILE_READ_WRITE

create (IN)

Indicates if the file is to be created if it does not exist. Valid values are:

OCI_FILE_TRUNCATE — Create a file regardless of whether it exists. If the file exists, overwrite the existing file.

OCI_FILE_EXCL — Fail if the file exists; otherwise, create a file.

OCI_FILE_CREATE — Open the file if it exists, and create it if it does not.

OCI_FILE_APPEND — Set the file pointer to the end of the file prior to writing. This flag can be used with the logical operator OR with OCI_FILE_CREATE.

type (IN)

File type. Valid values are:

OCI_FILE_TEXT

OCI_FILE_BIN

OCI_FILE_STDIN

OCI_FILE_STDOUT

OCI_FILE_STDERR

Returns

OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

OCIFileRead()

Purpose

Reads from a file into a buffer.

Syntax

sword OCIFileRead( void          *hndl, 
                   OCIError      *err, 
                   OCIFileObject *filep, 
                   void          *bufp, 
                   ub4           bufl, 
                   ub4           *bytesread );

Parameters

hndl (IN)

The OCI environment or user session handle.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

filep (IN/OUT)

A file identifier that uniquely references the file.

bufp (IN)

The pointer to a buffer into which the data is read. The length of the allocated memory is assumed to be bufl.

bufl (IN)

The length of the buffer in bytes.

bytesread (OUT)

The number of bytes read.

Comments

As many bytes as possible are read into the user buffer. The read ends either when the user buffer is full, or when it reaches end-of-file.

Returns

OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

OCIFileSeek()

Purpose

Changes the current position in a file.

Syntax

sword OCIFileSeek( void          *hndl, 
                   OCIError      *err, 
                   OCIFileObject *filep, 
                   uword         origin, 
                   ubig_ora      offset, 
                   sb1           dir );

Parameters

hndl (IN)

The OCI environment or user session handle.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

filep (IN/OUT)

A file identifier that uniquely references the file.

origin(IN)

The starting point from which to seek. Use one of the following values:

OCI_FILE_SEEK_BEGINNING (beginning)

OCI_FILE_SEEK_CURRENT (current position)

OCI_FILE_SEEK_END (end of file)

offset (IN)

The number of bytes from the origin where reading begins.

dir (IN)

The direction to go from the origin.

Note:

The direction can be either OCIFILE_FORWARD or OCIFILE_BACKWARD.

Comments

This function allows a seek past the end of the file. Reading from such a position causes an end-of-file condition to be reported. Writing to such a position does not work on all file systems. This is because some systems do not allow files to grow dynamically. They require that files be preallocated with a fixed size. Note that this function performs a seek to a byte location.

Returns

OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

OCIFileTerm()

Purpose

Terminates the OCIFile package. It must be called after the OCIFile package is no longer being used.

Syntax

sword OCIFileTerm( void     *hndl, 
                   OCIError *err );

Parameters

hndl (IN)

The OCI environment or user session handle.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

Returns

OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.

OCIFileWrite()

Purpose

Writes buflen bytes into the file.

Syntax

sword OCIFileWrite( void          *hndl, 
                    OCIError      *err, 
                    OCIFileObject *filep, 
                    void          *bufp, 
                    ub4           buflen, 
                    ub4           *byteswritten );

Parameters

hndl (IN)

The OCI environment or user session handle.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

filep (IN/OUT)

A file identifier that uniquely references the file.

bufp(IN)

The pointer to a buffer from which the data is written. The length of the allocated memory is assumed to be buflen.

buflen (IN)

The length of the buffer in bytes.

byteswritten (OUT)

The number of bytes written.

Returns

OCI_SUCCESS; OCI_INVALID_HANDLE; or OCI_ERROR.