Click or drag to resize

FRead4 Function

Read characters from a file into an allocated buffer.

Namespace:  XSharp.RT
Assembly:  XSharp.RT (in XSharp.RT.dll) Version: 2.4a
Syntax
 FUNCTION FRead4(
	ptrHandle AS IntPtr,
	ptrBufferVar AS IntPtr,
	dwBytes AS DWORD,
	lAnsi AS LOGIC
) AS DWORD
View Source

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: UInt32
The number of bytes to read into the buffer.
lAnsi
Type: Boolean
If FALSE an OEM to ANSI conversion is made.

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
FRead4() is the same as FRead3(), except that it provides you with the option of doing an OEM to ANSI conversion.
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 FRead4() after successfully opening a file to read 128 bytes into a buffer area:
X#
 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 FRead4(ptrHandle, cBuffer, F_BLOCK, FALSE) != F_BLOCK
14        ? DOSErrString(FError())
15            RETURN FALSE
16        ENDIF
17        FClose(ptrHandle)
18    ENDIF
19    MemFree(cBuffer)
20    RETURN TRUE
See Also