Library SimpleDNSResolver

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Classes

CSimpleDNSClient: COM (ActiveX) object implementing ISimpleDNSClient, a DNS resolver.

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Data

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Global Functions

LPTSTR WindowsGetErrorText(DWORD dwErrorCode, LPTSTR lpszBuf, DWORD dwSize);

DWORD WindowsSocketGetErrorText(DWORD dwErrorCode, LPTSTR *lplpszTemp);

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#include "SimpleDNSClient.h"

CSimpleDNSClient

/* -----------------------------------------------------------------

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LPTSTR WindowsGetErrorText(DWORD dwErrorCode, LPTSTR lpszBuf, DWORD dwSize);

#include "WindowsErrorText.h"

Purpose: return the text for a given Windows Error Code

Parameters:

in dwErrorCode: WIN32 error code (e.g. returned by "GetLastError")
in lpszBuf: buffer where the error text will be written
in dwSize: size of the buffer (maximum size for the error text)

Return value : LPTSTR = error text (points to lpszBuf)

Description : This function is a wrapper for many error-handling functions from WIN32. It searches for error text in the following locations:

In the Operating System, using function FormatMessage (...FORMAT_MESSAGE_FROM_SYSTEM...)
In an hard-coded table for Windows Socket (Winsock) error code (see function WindowsSocketGetErrorText())
In specific modules, using function FormatMessage (...FORMAT_MESSAGE_FROM_HMODULE...):

wininet.dll (Win32 Internet Errors)
mqutil.dll (Microsoft Message Queue Errors)

In Extended Internet Errors, using function InternetGetLastResponseInfo()

If no error text is found, this function still builds an error message with the format "Error Code 0x%X (%d)" (the error code is shown is hexadecimal and in decimal).

LPTSTR WindowsGetErrorText(DWORD dwErrorCode, LPTSTR lpszBuf, DWORD dwSize);

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DWORD WindowsSocketGetErrorText(DWORD dwErrorCode, LPTSTR *lplpszTemp);

#include "WindowsErrorText.h"

Purpose: return the clear-text message for a Windows Socket (winsock) error code.

Parameters:

in dwErrorCode: winsock error code (should be above WSABASEERR = 10000)
out lplpszTemp: clear-text error message

Return value : DWORD = length of the error message, or 0 if the error code cannot be mapped (not a Winsock error code).

Description : Winsock error codes cannot be correctly mapped to clear-text messages using WIN32 function FormatMessage (try it; you'll be surprised). This function uses an hard-coded table to map code to their real clear-text messages.

The calling application must free the string allocated in variable lplpszTemp (using WIN32 function LocalFree()).

DWORD WindowsSocketGetErrorText(DWORD dwErrorCode, LPTSTR *lplpszTemp);

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Generated from source by the Cocoon utilities on Wed Feb 09 17:55:46 2000 .

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