delphi – 链接sqlite3.obj会发出不满意的前向声明错误

以下是我们如何将源代码编译成.obj(一个包含FTS3,另一个没有它)：

del sqlite3.obj
devbccbinbcc32 -6 -O2 -c -d -DSQLITE_ENABLE_FTS3 -u- sqlite3.c
copy sqlite3.obj sqlite3fts3.obj
devbccbinbcc32 -6 -O2 -c -d -u- sqlite3.c

然后看一下SynSQLite3.pas单元.它包含一些所需外部文件的纯pascal或asm版本.

例如：

function _ftol: Int64;
// Borland C++ float to integer (Int64) conversion
asm
  jmp System.@Trunc  // FST(0) -> EDX:EAX,as expected by BCC32 compiler
end;

function _ftoul: Int64;
// Borland C++ float to integer (Int64) conversion
asm
  jmp System.@Trunc  // FST(0) -> EDX:EAX,as expected by BCC32 compiler
end;

function malloc(size: cardinal): Pointer; cdecl; { always cdecl }
// the SQLite3 database engine will use the FastMM4/SynScaleMM fast heap manager
begin
  GetMem(Result,size);
end;

procedure free(P: Pointer); cdecl; { always cdecl }
// the SQLite3 database engine will use the FastMM4 very fast heap manager
begin
  FreeMem(P);
end;

function realloc(P: Pointer; Size: Integer): Pointer; cdecl; { always cdecl }
// the SQLite3 database engine will use the FastMM4/SynScaleMM very fast heap manager
begin
  result := P;
  ReallocMem(result,Size);
end;

function memset(P: Pointer; B: Integer; count: Integer): pointer; cdecl; { always cdecl }
// a fast full pascal version of the standard C library function
begin
  result := P;
  FillChar(P^,count,B);
end;

procedure memmove(dest,source: pointer; count: Integer); cdecl; { always cdecl }
// a fast full pascal version of the standard C library function
begin
  Move(source^,dest^,count); // move() is overlapping-friendly
end;

procedure memcpy(dest,source: Pointer; count: Integer); cdecl; { always cdecl }
// a fast full pascal version of the standard C library function
begin
  Move(source^,count);
end;

function atol(P: pointer): integer; cdecl; { always cdecl }
// a fast full pascal version of the standard C library function
begin
  result := GetInteger(P);
end;

var __turbofloat: word; { not used,but must be present for linking }

// Borland C++ and Delphi share the same low level Int64 _ll*() functions:

procedure _lldiv;
asm
  jmp System.@_lldiv
end;

procedure _lludiv;
asm
  jmp System.@_lludiv
end;

procedure _llmod;
asm
  jmp System.@_llmod
end;

procedure _llmul;
asm
  jmp System.@_llmul
end;

procedure _llumod;
asm
  jmp System.@_llumod
end;

procedure _llshl;
asm
  jmp System.@_llshl
end;

procedure _llshr;
asm
{$ifndef ENHANCEDRTL} // need this code for Borland/CodeGear default System.pas
  shrd    eax,edx,cl
  sar     edx,cl
  cmp     cl,32
  jl      @@Done
  cmp     cl,64
  jge     @@RetSign
  mov     eax,edx
  sar     edx,31
  ret
@@RetSign:
  sar     edx,31
  mov     eax,edx
@@Done:
{$else}
  // our customized System.pas didn't forget to put _llshr in its interface :)
  jmp System.@_llshr
{$endif}
end;

procedure _llushr;
asm
  jmp System.@_llushr
end;

function strlen(p: PAnsiChar): integer; cdecl; { always cdecl }
// a fast full pascal version of the standard C library function
begin // called only by some obscure FTS3 functions (normal code use dedicated functions)
  result := SynCommons.StrLen(pointer(p));
end;

function memcmp(p1,p2: pByte; Size: integer): integer; cdecl; { always cdecl }
// a fast full pascal version of the standard C library function
begin
  if (p1<>p2) and (Size<>0) then
    if p1<>nil then
      if p2<>nil then begin
        repeat
          if p1^<>p2^ then begin
            result := p1^-p2^;
            exit;
          end;
          dec(Size);
          inc(p1);
          inc(p2);
        until Size=0;
        result := 0;
      end else
      result := 1 else
    result := -1 else
  result := 0;
end;

function strncmp(p1,p2: PByte; Size: integer): integer; cdecl; { always cdecl }
// a fast full pascal version of the standard C library function
var i: integer;
begin
  for i := 1 to Size do begin
    result := p1^-p2^;
    if (result<>0) or (p1^=0) then
      exit;
    inc(p1);
    inc(p2);
  end;
  result := 0;
end;


function localtime(t: PCardinal): pointer; cdecl; { always cdecl }
// a fast full pascal version of the standard C library function
var uTm: TFileTime;
    lTm: TFileTime;
    S: TSystemTime;
begin
  Int64(uTm) := (Int64(t^) + 11644473600)*10000000; // unix time to dos file time
  FileTimeToLocalFileTime(uTM,lTM);
  FileTimeToSystemTime(lTM,S);
  with atm do begin
    tm_sec := S.wSecond;
    tm_min := S.wMinute;
    tm_hour := S.wHour;
    tm_mday := S.wDay;
    tm_mon := S.wMonth-1;
    tm_year := S.wYear-1900;
    tm_wday := S.wDayOfWeek;
  end;
  result := @atm;
end;

你会发现这个单元不仅仅是SQLite3的静态链接.请注意,即使我们的mORMot ORM客户端 – 服务器框架使用它,也不需要使用此ORM来使用SQLite3类.见this article for additional details.

如果您迷失在我们的源代码库中(使用伟大的FOSSIL项目),read this.