Fileflush

Home › Operating System Functions › FileFlush

FileFlush

Writes buffered output for one or all open files to the system, or on to disk.

Syntax

Declare Function FileFlush ( ByVal filenum As Long = -1, ByVal systembuffers As Long = 0 ) As Long

Parameters

• filenum
• systembuffers

Description

FileFlush writes application buffered output to the underlying stream, and if systembuffers is non-zero, to the underlying physical device as well.

In the form FileFlush(filenum), the application output buffer for a specific file are written. And in the form FileFlush, all application buffers are written to the system. Typically, when a file is opened, the stream will be block buffered for binary and random files, and line buffered for append and output files. The FileFlush function overrides the normal buffering of the application and immediately writes buffered output to the system. The system may have it's own buffers as well.

In the form FileFlush(filenum,1), both the application buffer is flushed and the underlying system buffer is flushed to physical device. In the form FileFlush(,1), all application buffers are flushed and all underlying system buffers are flushed to physical device.

Return Value

Returns zero (0) for success or an error code if file buffers could not be flushed.

Remarks

Usage

#include "file.bi"

result = FileFlush()

result = FileFlush( filenum )

result = FileFlush( filenum, systembuffers )

Differences from QB

• New to FreeBASIC.

See also

• Close

Examples

#include "file.bi"

Dim As Long f1, f2

Dim As String s

Print "File length", "File string"

f1 = FreeFile

Open "fileflushtest.txt" For Output As #f1

Print #f1, "successful file flush"

f2 = FreeFile

Open "fileflushtest.txt" For Input As #f2

Line Input #f2, s

Print FileLen("fileflushtest.txt"), "'" & s & "'"  '' the string is not yet physically written to the file

FileFlush(f1)

Line Input #f2, s

Print FileLen("fileflushtest.txt"), "'" & s & "'"  '' the string is now physically written to the file

Close #f2

Close #f1

Sleep

Output (Windows):

File length   File string
 0            ''
 23           'successful file flush'

---

Category: Operating System Functions
Kind: function

---

Reproduced from the FreeBASIC Wiki Manual under the GNU Free Documentation License 1.3 — with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. Copyright © the FreeBASIC project and wiki contributors. See License.