NETMSG.C

/*++ 
 
Copyright 1996 - 1997 Microsoft Corporation 
 
Module Name: 
 
    netmsg.c 
 
Abstract: 
 
    The following sample illustrates how to display error text associated with 
    Networking related error codes, in addition to displaying error text 
    associated with system related error codes. 
 
    If the supplied error number is in a specific range, the netmsg.dll 
    message module is loaded and used to lookup the specified error number 
    with the FormatMessage() Win32 API. 
 
Author: 
 
    Scott Field (sfield)    29-Mar-96 
 
--*/ 
 
#include <windows.h> 
#include <stdio.h> 
 
#include <lmerr.h> 
 
void 
DisplayErrorText( 
    DWORD dwLastError 
    ); 
 
#define RTN_OK 0 
#define RTN_USAGE 1 
#define RTN_ERROR 13 
 
int 
__cdecl 
main( 
    int argc, 
    char *argv[] 
    ) 
{ 
    if(argc != 2) { 
        fprintf(stderr,"Usage: %s <error number>\n", argv[0]); 
        return RTN_USAGE; 
    } 
 
    DisplayErrorText( atoi(argv[1]) ); 
 
    return RTN_OK; 
} 
 
void 
DisplayErrorText( 
    DWORD dwLastError 
    ) 
{ 
    HMODULE hModule = NULL; // default to system source 
    LPSTR MessageBuffer; 
    DWORD dwBufferLength; 
 
    DWORD dwFormatFlags = FORMAT_MESSAGE_ALLOCATE_BUFFER | 
        FORMAT_MESSAGE_IGNORE_INSERTS | 
        FORMAT_MESSAGE_FROM_SYSTEM ; 
 
    // 
    // if dwLastError is in the network range, load the message source 
    // 
 
    if(dwLastError >= NERR_BASE && dwLastError <= MAX_NERR) { 
        hModule = LoadLibraryEx( 
            TEXT("netmsg.dll"), 
            NULL, 
            LOAD_LIBRARY_AS_DATAFILE 
            ); 
 
        if(hModule != NULL) 
            dwFormatFlags |= FORMAT_MESSAGE_FROM_HMODULE; 
    } 
 
    // 
    // call FormatMessage() to allow for message text to be acquired 
    // from the system or the supplied module handle 
    // 
 
    if(dwBufferLength = FormatMessageA( 
        dwFormatFlags, 
        hModule, // module to get message from (NULL == system) 
        dwLastError, 
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // default language 
        (LPSTR) &MessageBuffer, 
        0, 
        NULL 
        )) 
    { 
        DWORD dwBytesWritten; 
 
        // 
        // Output message string on stderr 
        // 
        WriteFile( 
            GetStdHandle(STD_ERROR_HANDLE), 
            MessageBuffer, 
            dwBufferLength, 
            &dwBytesWritten, 
            NULL 
            ); 
 
        // 
        // free the buffer allocated by the system 
        // 
        LocalFree(MessageBuffer); 
    } 
 
    // 
    // if we loaded a message source, unload it 
    // 
    if(hModule != NULL) 
        FreeLibrary(hModule); 
}