4D v13.4
VOLUME ATTRIBUTES
- 4D Language Reference
-
- System Documents
-
- System Documents
- Append document
- CLOSE DOCUMENT
- Convert path POSIX to system
- Convert path system to POSIX
- COPY DOCUMENTUpd
- CREATE ALIAS
- Create document
- CREATE FOLDERUpd
- DELETE DOCUMENT
- DELETE FOLDER
- Document creator
- DOCUMENT LISTUpd
- Document type
- FOLDER LIST
- GET DOCUMENT ICON
- Get document position
- GET DOCUMENT PROPERTIES
- Get document size
- Get localized document path
- MAP FILE TYPES
- MOVE DOCUMENT
- Open document
- RESOLVE ALIAS
- Select documentUpd
- Select folder
- SET DOCUMENT CREATOR
- SET DOCUMENT POSITION
- SET DOCUMENT PROPERTIES
- SET DOCUMENT SIZE
- SET DOCUMENT TYPE
- SHOW ON DISK
- Test path name
- VOLUME ATTRIBUTES
- VOLUME LIST
VOLUME ATTRIBUTES
| VOLUME ATTRIBUTES ( volume ; size ; used ; free ) | ||||||||
| Parameter | Type | Description | ||||||
| volume | String |
|
Volume name | |||||
| size | Real |
|
Volume size expressed in bytes | |||||
| used | Real |
|
Used space expressed in bytes | |||||
| free | Real |
|
Free space expressed in bytes | |||||
The VOLUME ATTRIBUTES command returns, expressed in bytes, the size, the used space and the free space for the volume whose name you pass in volume.
Note: If volume indicates a non-mounted remote volume, the OK variable is set to 0 and the three parameters return -1.
Your application includes some batch operations running the night or the week-end that store huge temporary files on disk. To make this process as automatic and flexible as possible, you write a routine that will automatically find the first volume whose free space is sufficient for your temporary files. You might write the following project method:
` Find volume for space Project Method
` Find volume for space ( Real ) -> String
` Find volume for space ( Space needed in bytes ) -> Volume name or Empty string
C_STRING(31;$0)
C_STRING(255;$vsDocName)
C_LONGINT($vlNbVolumes;$vlVolume)
C_REAL($1;$vlSize;$vlUsed;$vlFree)
C_TIME($vhDocRef)
` Initialize function result
$0:=""
` Protect all I/O operations with an error interruption method
ON ERR CALL("ERROR METHOD")
` Get the list of the volumes
ARRAY STRING(31;$asVolumes;0)
gError:=0
VOLUME LIST($asVolumes)
If(gError=0)
` If running on windows, skip the (usual) two floppy drives
If(On Windows)
$vlVolume:=Find in array($asVolumes;"A:\\")
If($vlVolume>0)
DELETE FROM ARRAY($asVolumes;$vlVolume)
End if
$vlVolume:=Find in array($asVolumes;"B:\\")
If($vlVolume>0)
DELETE FROM ARRAY($asVolumes;$vlVolume)
End if
End if
$vlNbVolumes:=Size of array($asVolumes)
` For each volume
For($vlVolume;1;$vlNbVolumes)
` Get the size, used space and free space
gError:=0
VOLUME ATTRIBUTES($asVolumes{$vlVolume};$vlSize;$vlUsed;$vlFree)
If(gError=0)
` Is the free space large enough (plus an extra 32K) ?
If($vlFree>=($1+32768))
` If so, check if the volume is unlocked...
$vsDocName:=$asVolumes{$vlVolume}+Char(Directory symbol)+"XYZ"+String(Random)+".TXT"
$vhDocRef:=Create document($vsDocName)
If(OK=1)
CLOSE DOCUMENT($vhDocRef)
DELETE DOCUMENT($vsDocName)
` If everything's fine, return the name of the volume
$0:=$asVolumes{$vlVolume}
$vlVolume:=$vlNbVolumes+1
End if
End if
End if
End for
End if
ON ERR CALL("")Once this project method is added to your application, you can for instance write:
$vsVolume:=Find volume for space(100*1024*1024)
If($vsVolume#"")
` Continue
Else
ALERT("A volume with at least 100 MB of free space is required!")
End if
Product: 4D
Theme: System Documents
Number:
472
Created: 4D v6
