FReadText Function | |
Read characters from a file into a buffer variable that is passed by reference.
Namespace:
XSharp.Core
Assembly:
XSharp.Core (in XSharp.Core.dll) Version: 2.21
Syntax FUNCTION FReadText(
ptrHandle AS IntPtr,
cBufferVar REF STRING,
dwBytes AS DWORD
) AS DWORD
public static uint FReadText(
IntPtr ptrHandle,
ref string cBufferVar,
uint dwBytes
)
Request Example
View SourceParameters
- ptrHandle
- Type: IntPtr
The handle of the file to read from. - cBufferVar
- Type: String
A variable used to store data read from the specified file.
If the length of cBufferVar is less than dwBytes, a new string whose length is the minimum of dwBytes and the remaining bytes in the file is allocated. cBufferVar must be passed by reference and, therefore, must be prefaced by the pass-by-reference operator (@).
- dwBytes
- Type: DWord
The number of bytes to read into the buffer.
Return Value
Type:
DWord
The number of bytes successfully read.
A return value less than
dwBytes or 0 indicates end-of-file or some other read error. FError() can be used to determine the specific error.
Remarks
FReadText() is the same as FRead() except that an OEM to ANSI conversion is made if SetAnsi() is FALSE.
Remarks Tip |
---|
The low level File IO functions in the X# runtime are using .Net filestreams in the background.
That means that the file handles returned by FOpen() and FCreate() are not 'normal' file handles,
but unique identifiers that are used to find the underlying stream object in a collection of
streams in the runtime.
That also means that you can't use file handles for functions such as FRead() and FWrite() that were not
created in the X# runtime.
If you want to access the underlying FileStream, then you should call the
function FGetStream(IntPtr) |
Examples
This example uses FRead() after successfully opening a file to read 128 bytes into a buffer area:
1DEFINE F_BLOCK := 128
2...
3cBuffer := Space(F_BLOCK)
4ptrHandle := FOpen("temp.txt")
5IF FError() != 0
6 ? DOSErrString(FError())
7ELSE
8 IF FReadText(ptrHandle, @cBuffer, F_BLOCK) <paramref name="" /> F_BLOCK
9 ? DOSErrString(FError())
10 ENDIF
11 FClose(ptrHandle)
12ENDIF
See Also