FRead4 Function | |
Read characters from a file into an allocated buffer.
Namespace:
XSharp.Core
Assembly:
XSharp.Core (in XSharp.Core.dll) Version: 2.21
Syntax FUNCTION FRead4(
ptrHandle AS IntPtr,
ptrBufferVar AS BYTE[],
dwBytes AS DWORD,
lAnsi AS LOGIC
) AS DWORD
public static uint FRead4(
IntPtr ptrHandle,
byte[] ptrBufferVar,
uint dwBytes,
bool lAnsi
)
Request Example
View SourceParameters
- ptrHandle
- Type: IntPtr
The handle of the file to read from. - ptrBufferVar
- Type: Byte
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.
An array of bytes to store the data read from the specified file. The length of this variable must be greater than or equal to the number of bytes in the next parameter. - dwBytes
- Type: DWord
The number of bytes to read into the buffer. - lAnsi
- Type: Logic
If FALSE an OEM to ANSI conversion is made.
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
FRead4() is the same as FRead3(), except that it provides you with the option of doing an OEM to ANSI conversion.
Remarks Tip |
---|
Conversions between OEM en Ansi were relevant in an Ansi environment like Visual Objects.
In a Unicode environment this conversion is noto much a conversion between OEM and Ansi but a
conversion between either Unicode and Ansi or Unicode and OEM.
For these conversions the runtime uses the current values of the
Windows Codepage
and
DOS Codepage.
|
Examples
This example uses FRead4() after successfully opening a file to read 128 bytes into a buffer area:
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