This function block of the ⇘ CAA_File.library reads the file, which was previously opened via ⇘ FILE.Open. If less characters can be read than specified in ”szBuffer”, the function block returns an active ”xDone” and indicates the current number of characters in ”szSize”. The size of the target memory structure for the bytes to be read and the number of bytes to be read will not be checked.
If the stability of the pointer on the data structures and their contents cannot be guaranteed in case of an online change, an online change must be avoided with the help of functions from the ”CAA.Application library”.
Input:
|
xExecute |
BOOL |
see: ⇘ “CAA 指南” |
|
xAbort |
BOOL |
see: ⇘ “CAA 指南” |
|
udiTimeOut |
UDINT |
|
|
hFile |
CAA.HANDLE |
File handle |
|
pBuffer |
CAA.PVOID |
Target address for the first byte to be read; can be retrieved via operator ADR |
|
szBuffer |
CAA.SIZE |
Maximum number of bytes to be read; can be retrieved via operator sizeof |
Output:
|
xDone |
BOOL |
see: Guidelines for CAA libs |
|
xBusy |
BOOL |
see: Guidelines for CAA libs |
|
xError |
BOOL |
see: Guidelines for CAA libs |
|
xAborted |
BOOL |
see: Guidelines for CAA libs |
|
eError |
FILE.ERROR |
Error ID |
|
szSize |
CAA.SIZE |
Current number of successfully read bytes; this value is already valid before xDone has been set |