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FRead Function (IntPtr, IntPtr, DWord)

X#
Read characters from a file into an allocated buffer.

Namespace:  XSharp.RT
Assembly:  XSharp.RT (in XSharp.RT.dll) Version: 2.19
Syntax
Copy
 FUNCTION FRead(
	ptrHandle AS IntPtr,
	ptrBufferVar AS IntPtr,
	dwBytes AS DWORD
) AS DWORD
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Parameters

ptrHandle
Type: IntPtr
The handle of the file to read from.
ptrBufferVar
Type: IntPtr
Pointer to an allocated buffer used to store data read from the specified file.
The length of this variable must be greater than or equal to dwBytes.
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
FRead3() is the same as FRead(), except that the name of the buffer variable is a pointer and is not passed by reference. See FRead() for details. This function is assumed to handle raw binary data and is not dependent upon the status of SetAnsi(). FReadText() and FRead4(), on the other hand, are dependent upon SetAnsi().
Remarks
Tip Tip
This function is included for compatibility. We do not recomment using static memory for file i/o operations. We recommend that you use the function overload that takes a byte array parameter in stead.
Examples
This example uses FRead3() after successfully opening a file to read 128 bytes into a buffer area:
X#
Copy
 1DEFINE F_BLOCK := 128
 2Function Start()
 3    LOCAL cBuffer AS PTR
 4    cBuffer := MemAlloc(F_BLOCK)
 5    IF cBuffer = NULL PTR
 6        RETURN FALSE
 7    ENDIF
 8    ptrHandle := FOpen2("temp.txt", FO_READ)
 9    IF ptrHandle = F_ERROR
10        ? DOSErrString(FError())
11        RETURN FALSE
12    ELSE
13        IF FRead3(ptrHandle, cBuffer, F_BLOCK) <paramref name="" /> F_BLOCK
14            ? DOSErrString(FError())
15            RETURN FALSE
16        ENDIF
17        FClose(ptrHandle)
18    ENDIF
19    MemFree(cBuffer)
20    RETURN TRUE
See Also