Private Declare Function GetPrivateProfileSection Lib "kernel32.dll" Alias "GetPrivateProfileSectionA" (ByVal lpAppName As String, ByVal lpReturnedString As String, ByVal nSize As Long, ByVal lpFileName As String) As Long
Private Declare Function GetPrivateProfileSectionNames Lib "kernel32.dll" Alias "GetPrivateProfileSectionNamesA" (ByVal lpszReturnBuffer As String, ByVal nSize As Long, ByVal lpFileName As String) As Long
Private Declare Function WritePrivateProfileString Lib "kernel32.dll" Alias "WritePrivateProfileStringA" (ByVal lpApplicationName As String, ByVal lpKeyName As Any, ByVal lpString As Any, ByVal lpFileName As String) As Long
Public Sub MergeIniFiles(ByRef vsFirstFile As String, ByRef vsSecondFile As String, Optional ByVal vsDestFile As String)
Dim sBuffer As String
Dim nLength As Long
Dim iSection As Long
Dim iLine As Long
Dim xsSections() As String
Dim xsLines() As String
Dim nPos As Long
Dim nBuffserSize As Long
   If LenB(vsDestFile) Then
       FileCopy vsSecondFile, vsDestFile
   Else
       vsDestFile = vsSecondFile
   End If
   
   nBuffserSize = 0
   Do
       nBuffserSize = nBuffserSize + &H4000&
       sBuffer = Space$(nBuffserSize)
       nLength = GetPrivateProfileSectionNames(sBuffer, nBuffserSize, vsFirstFile)
   Loop While nLength = nBuffserSize - 2
   xsSections = Split(Left$(sBuffer, nLength), vbNullChar)
   For iSection = 0 To UBound(xsSections)
       If LenB(xsSections(iSection)) Then
           nBuffserSize = 0
           Do
               nBuffserSize = nBuffserSize + &H4000&
               sBuffer = Space$(nBuffserSize)
               nLength = GetPrivateProfileSection(xsSections(iSection), sBuffer, nBuffserSize, vsFirstFile)
           Loop While nLength = nBuffserSize - 2
           xsLines = Split(Left$(sBuffer, nLength), vbNullChar)
           
           For iLine = 0 To UBound(xsLines)
               nPos = InStr(xsLines(iLine), "=")
               If nPos Then
                   WritePrivateProfileString xsSections(iSection), Left$(xsLines(iLine), nPos - 1), Mid$(xsLines(iLine), nPos + 1), vsDestFile
               End If
           Next iLine
       End If
   Next iSection
End Sub 

uses IniFiles;
procedure IncludeIniFile(Src, Dest : TIniFile);
var PE,NA,NB : integer;
    VL,SL : TStringList;
    VID,VVL : String;
begin
  VL := TStringList.Create;
  SL := TStringList.Create;
  try
    SL.BeginUpdate;
    try
      Src.ReadSections(SL);
    finally
      SL.EndUpdate;
    end;
    if SL.Count > 0 then
      for NA := 0 to SL.Count-1 do
      begin
        VL.BeginUpdate;
        try
          Src.ReadSectionValues(SL[NA],VL);
        finally
          VL.EndUpdate;
        end;
        if VL.Count > 0 then
          for NB := 0 to VL.Count-1 do
          begin
            PE  := Pos('=',VL[NB]);
            VID := Copy(VL[NB], 1, PE-1);
            VVL := Copy(VL[NB], PE+1, Length(VL[NB])-PE);
            Dest.WriteString(SL[NA],VID,VVL);
          end;
      end;
  finally
    SL.Free;
    VL.Free;
  end;
end;

PROCEDURE FusionneINI(sINISource, sINIDestination)
// sINISource : Chemin du fichier .INI qui sera copié dans la destination
// sINIDestination : Chemin du fichier .INI qui recevra le fichier source
// Aprés traitement sINIDestination a son contenu initial et en plus celui de sINISource
// Si une entrée est commune, c'est celle de sINISource qui est conservée au final
// Si sINIDestination est vide ou inexistant, il deviendra sINISource

sListeSectionSource, sSection sont des chaines
sListeMotcleSource, sMotCle sont des chaines

sListeSectionSource = INILit("","","", sINISource)
POUR TOUTE CHAINE sSection DE sListeSectionSource SEPAREE PAR RC
 sListeMotcleSource = INILit(sSection, "", "", sINISource)
 POUR TOUTE CHAINE sMotCle DE sListeMotcleSource SEPAREE PAR RC
    SI sSection <> "" ET sMotCle <> "" ALORS
       INIEcrit(sSection, sMotCle, ...
             INILit(sSection, sMotCle, "", sINISource),...
             sINIDestination)
    FIN
 FIN
FIN