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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: 2.5
Syntax
 FUNCTION FReadText(
	ptrHandle AS IntPtr,
	cBufferVar REF STRING,
	dwBytes AS DWORD
) AS DWORD

Parameters

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: UInt32
The number of bytes to read into the buffer.

Return Value

Type: UInt32
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 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()
Examples
This example uses FRead() after successfully opening a file to read 128 bytes into a buffer area:
X#
 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) <> F_BLOCK
 9        ? DOSErrString(FError())
10    ENDIF
11    FClose(ptrHandle)
12ENDIF
See Also