Admin at 19:21, 17 January 2017

2017-01-17T19:21:35Z

Admin at 19:21, 17 January 2017

2017-01-17T19:21:19Z

Admin: Created page with "= Action = Function: Returns the position of the next Byte to be read or written Statement: Sets the position of the next Byte to be read or wr..."

2013-02-11T22:53:50Z

Created page with "= Action = Function: Returns the position of the next Byte to be read or written Statement: Sets the position of the next Byte to be read or wr..."

New page

= Action =

Function: Returns the position of the next Byte to be read or written

Statement: Sets the position of the next Byte to be read or written

 

 

= Syntax =

Function: NextReadWrite = SEEK (#bFileNumber)

Statement: SEEk #bFileNumber, NewPos

 

 

= Remarks =
<div style="padding: 0px; margin: 0px 0px 0px 4px;">
{| width="609" cellspacing="0" cellpadding="1" border="1" style="border: 2px solid rgb(0, 0, 0); border-spacing: 0px; border-collapse: collapse;"
|- style="vertical-align: top;"
| valign="top" width="20%" style="width: 118px; border: 1px solid rgb(0, 0, 0);" |
bFileNumber

| valign="top" width="100%" style="width: 482px; border: 1px solid rgb(0, 0, 0);" |
(Byte) Filenumber, which identifies an opened file

|- style="vertical-align: top;"
| valign="top" width="20%" style="width: 118px; border: 1px solid rgb(0, 0, 0);" |
NextReadWrite

| valign="top" width="100%" style="width: 482px; border: 1px solid rgb(0, 0, 0);" |
A Long Variable, which is assigned with the Position of the next Byte to be read or written (1-based)

|- style="vertical-align: top;"
| valign="top" width="20%" style="width: 118px; border: 1px solid rgb(0, 0, 0);" |
NewPos

| valign="top" width="100%" style="width: 482px; border: 1px solid rgb(0, 0, 0);" |
A Long variable that holds the new position the file pointer must be set too.

|}
</div>
 

This function returns the position of the next Byte to be read or written. If an error occurs, 0 is returned. Check DOS-Error in variable gbDOSError.

 

The statement also returns an error in the gbDOSerror variable in the event that an error occurs.

You can for example not set the file position behinds the file size.

 

In VB the file is filled with 0 bytes when you set the file pointer behind the size of the file. For embedded systems this does not seem a good idea.

 

 

Seek and Loc seems to do the same function, but take care : the seek function will return the position of the next read/write, while the Loc function returns the position of the last read/write. You may say that Seek = Loc+1.

 

 

[[File:Notice.jpg|left|Notice.jpg]] In QB/VB you can use seek to make the file bigger. When a file is 100 bytes long, setting the file pointer to 200 will increase the file with 100 bytes. By design this is not the case in AVR-DOS.

 

 

 

= See also =

[[INITFILESYSTEM]] , [[OPEN]] , [[CLOSE]], [[FLUSH]] , [[PRINT]], [[LINE INPUT]], [[LOC]], [[LOF]] , [[EOF]] , [[FREEFILE]] , [[FILEATTR]] , [[BSAVE]] , [[BLOAD]] ,[[KILL]] , [[DISKFREE]] , [[DISKSIZE]] , [[GET]] , [[PUT]] , [[FILEDATE]] , [[FILETIME]] , [[FILEDATETIME]] , [[DIR]] , [[FILELEN]] , [[WRITE]] , [[INPUT]]

 

 

 

= ASM =
<div style="padding: 0px; margin: 0px 0px 0px 4px;">
{| width="634" cellspacing="0" cellpadding="1" border="1" style="border: 2px solid rgb(0, 0, 0); border-spacing: 0px; border-collapse: collapse;"
|- style="vertical-align: top;"
| valign="top" width="23%" style="width: 143px; border: 1px solid rgb(0, 0, 0);" |
Function

Calls

| valign="top" width="29%" style="width: 180px; border: 1px solid rgb(0, 0, 0);" |
_FileSeek

| valign="top" width="59%" style="width: 299px; border: 1px solid rgb(0, 0, 0);" |
 

|- style="vertical-align: top;"
| valign="top" width="23%" style="width: 143px; border: 1px solid rgb(0, 0, 0);" |
Input

| valign="top" width="29%" style="width: 180px; border: 1px solid rgb(0, 0, 0);" |
r24: filenumber

| valign="top" width="59%" style="width: 299px; border: 1px solid rgb(0, 0, 0);" |
X: Pointer to Long-variable, which gets the result

|- style="vertical-align: top;"
| valign="top" width="23%" style="width: 143px; border: 1px solid rgb(0, 0, 0);" |
Output

| valign="top" width="29%" style="width: 180px; border: 1px solid rgb(0, 0, 0);" |
r25: Errorcode

| valign="top" width="59%" style="width: 299px; border: 1px solid rgb(0, 0, 0);" |
C-Flag: Set on Error

|}
</div>
 
<div style="padding: 0px; margin: 0px 0px 0px 4px;">
{| width="634" cellspacing="0" cellpadding="1" border="1" style="border: 2px solid rgb(0, 0, 0); border-spacing: 0px; border-collapse: collapse;"
|- style="vertical-align: top;"
| valign="top" width="23%" style="width: 143px; border: 1px solid rgb(0, 0, 0);" |
Statement

Calls

| valign="top" width="28%" style="width: 173px; border: 1px solid rgb(0, 0, 0);" |
_FileSeekSet

| valign="top" width="58%" style="width: 306px; border: 1px solid rgb(0, 0, 0);" |
 

|- style="vertical-align: top;"
| valign="top" width="23%" style="width: 143px; border: 1px solid rgb(0, 0, 0);" |
Input

| valign="top" width="28%" style="width: 173px; border: 1px solid rgb(0, 0, 0);" |
r24: filenumber

| valign="top" width="58%" style="width: 306px; border: 1px solid rgb(0, 0, 0);" |
X: Pointer to Long-variable with the position

|- style="vertical-align: top;"
| valign="top" width="23%" style="width: 143px; border: 1px solid rgb(0, 0, 0);" |
Output

| valign="top" width="28%" style="width: 173px; border: 1px solid rgb(0, 0, 0);" |
r25: Errorcode

| valign="top" width="58%" style="width: 306px; border: 1px solid rgb(0, 0, 0);" |
C-Flag: Set on Error

|}
</div>
 

 

 

= Partial Example =

 <source lang="bascomavr">
Open "test.biN"for Binary As #2
Put#2 , B ' write a byte
Put#2 , W ' write a word
Put#2 , L ' write a long
Ltemp = Loc(#2) + 1 ' get the position of the next byte
Print Ltemp ; " LOC" ' store the location of the file pointer
Print Seek(#2) ; " = LOC+1"
Close #2

'now open the file again and write only the single
Open "test.bin" For Binary As #2
Seek#2 , Ltemp ' set the filepointer
Sn = 1.23 ' change the single value so we can check it better
Put #2 , Sn = 1 'specify the file position
Close #2
</source> {{Languages}}

[[Category:BASCOM Language Reference]]

@@ Line 188: / Line 188: @@
 </source>
-= <span class="f_Header">Partial Example 2</span> =
+= <span class="f_Header">Example 2</span> =
 <br/><source lang="bascomavr">

@@ Line 186: / Line 186: @@
 Put #2 , Sn = 1 'specify the file position
 Close #2
-</source><br/>{{Languages}}
+</source>
 [[Category:BASCOM Language Reference]]

SEEK - Revision history

Admin at 19:21, 17 January 2017

Admin at 19:21, 17 January 2017

Admin: Created page with "= Action = Function: Returns the position of the next Byte to be read or written Statement: Sets the position of the next Byte to be read or wr..."