FileAttr
Returns information about an open file number
#include "file.bi"
result = FileAttr( filenum, [ returntype ] )
or
#include "vbcompat.bi"
result = FileAttr( filenum, [ returntype ] )
filenum
A value associated with the return type, otherwise 0 on error.
Information about the file number is returned based on the supplied returntype
For File Mode, returntype = 1 (fbFileAttrMode) the return value is the sum of one or more of the following values:
For File Handle, returntype = 2 (fbFileAttrHandle), the return value is the file handle as supplied by the C Runtime for file-type devices.
On Windows only: For File Handle, returntype = 2 (fbFileAttrHandle), the value returned for COM devices is the handle returned by CreateFile() when the device was first opened. The value returned for LPT devices is the handle returned by OpenPrinter() when the device was first opened. This handle value can be passed to other Windows API functions.
On Linux only: For File Handle, returntype = 2 (fbFileAttrHandle), the value returned for COM devices is the file descriptor returned by open() when the device was first opened.
For Encoding, returntype = 3 (fbFileAttrEncoding), the return value is one of the following values:
Syntax
Usage
#include "file.bi"
result = FileAttr( filenum, [ returntype ] )
or
#include "vbcompat.bi"
result = FileAttr( filenum, [ returntype ] )
Parameters
filenum
The file number of a file or device opened with Open
returntypeAn integer value indicating the type of information to return.
Return Value
A value associated with the return type, otherwise 0 on error.
Description
Information about the file number is returned based on the supplied returntype
| Value | Description | constant |
| 1 | File Mode | fbFileAttrMode |
| 2 | File Handle | fbFileAttrHandle |
| 3 | Encoding | fbFileAttrEncoding |
| Value | File Mode | Constant |
| 1 | Input | fbFileModeInput |
| 2 | Output | fbFileModeOutput |
| 4 | Random | fbFileModeRandom |
| 8 | Append | fbFileModeAppend |
| 32 | Binary | fbFileModeBinary |
On Windows only: For File Handle, returntype = 2 (fbFileAttrHandle), the value returned for COM devices is the handle returned by CreateFile() when the device was first opened. The value returned for LPT devices is the handle returned by OpenPrinter() when the device was first opened. This handle value can be passed to other Windows API functions.
On Linux only: For File Handle, returntype = 2 (fbFileAttrHandle), the value returned for COM devices is the file descriptor returned by open() when the device was first opened.
For Encoding, returntype = 3 (fbFileAttrEncoding), the return value is one of the following values:
| Value | Encoding | Constant |
| 0 | Ascii | fbFileEncodASCII |
| 1 | UTF-8 | fbFileEncodUTF8 |
| 2 | UTF-16 | fbFileEncodUTF16 |
| 3 | UTF-32 | fbFileEncodUTF32 |
Example
#include "vbcompat.bi"
#include "crt.bi"
Dim f As FILE Ptr, i As Integer
'' Open a file and write some text to it
Open "test.txt" For Output As #1
f = Cast( FILE Ptr, FileAttr( 1, fbFileAttrHandle ))
For i = 1 To 10
fprintf( f, !"Line %i\n", i )
Next i
Close #1
'' re-open the file and read the text back
Open "test.txt" For Input As #1
f = Cast( FILE Ptr, FileAttr( 1, fbFileAttrHandle ))
While feof(f) = 0
i = fgetc(f)
Print Chr(i);
Wend
Close #1
#include "crt.bi"
Dim f As FILE Ptr, i As Integer
'' Open a file and write some text to it
Open "test.txt" For Output As #1
f = Cast( FILE Ptr, FileAttr( 1, fbFileAttrHandle ))
For i = 1 To 10
fprintf( f, !"Line %i\n", i )
Next i
Close #1
'' re-open the file and read the text back
Open "test.txt" For Input As #1
f = Cast( FILE Ptr, FileAttr( 1, fbFileAttrHandle ))
While feof(f) = 0
i = fgetc(f)
Print Chr(i);
Wend
Close #1
Differences from QB
- None for returntype = 1
- QBasic and 16-bit Visual Basic returned DOS file handle for returntype = 2
- returntype = 3 is new to FreeBASIC
See also