问题加载 .dylib Delphi 10.3.3

Question

加载动态库的问题。加载库部分有效，但 GetProcAddress 始终返回 nil。下面我写的小简单。如果 pcap_findalldevs 为 nil，它会打印出来，在我的情况下它总是 nil 并且与任何其他 libpcap 函数相同的问题。

program Project7;

{$APPTYPE CONSOLE}
{$R *.res}

uses
  System.SysUtils, pcap;

var
  h: THandle;

begin
  try
    { TODO -oUser -cConsole Main : Insert code here }
    begin
      h := LoadLibrary('libpcap.dylib');
      if h <> 0 then
      begin
        pcap_findalldevs := GetProcAddress(h, 'pcap_findalldevs');
        Writeln('Is pcap_findalldevs loaded ' +
          BoolToStr(Assigned(pcap_findalldevs)));
        Readln;
      end;
    end;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.

我不确定是否需要 Pcap 单元源，所以我还是要发布它。

unit Pcap;

interface

uses
{$IFDEF  WIN32}
  Windows, WinSock, {$IFEND} Bpf, System.SysUtils;

  // ----------------------------------------------------------------------------
  // Constant Definition
  // ----------------------------------------------------------------------------
const
  PCAP_VERSION_MAJOR = 2;
  PCAP_VERSION_MINOR = 4;
  PCAP_ERRBUF_SIZE = 256;
  PCAP_IF_LOOPBACK = $00000001; { interface is loopback }
  RPCAP_RMTAUTH_NULL = 0;
  RPCAP_RMTAUTH_PWD = 1;
  PCAP_OPENFLAG_PROMISCUOUS = 1;
  PCAP_OPENFLAG_SERVEROPEN_DP = 2;
  PCAP_OPENFLAG_UDP_DP = 4;

  MODE_CAPT = 0;
  MODE_STAT = 1;
  MODE_MON = 2;

  // ----------------------------------------------------------------------------
  // Type Definition
  // ----------------------------------------------------------------------------
type

  u_char = Char;
  u_short = Word;
  u_int = LongWord;
  u_long = LongWord;
  pu_char = ^byte;
  pu_short = ^Word;
  pu_int = ^LongWord;
  pu_long = ^LongWord;

  SunB = record
    s_b1, s_b2, s_b3, s_b4: u_char;
  end;

  SunW = record
    s_w1, s_w2: u_short;
  end;

  PInAddr = ^TInAddr;

  TInAddr = record
    case integer of
      0:
        (S_un_b: SunB);
      1:
        (S_un_w: SunW);
      2:
        (S_addr: u_long);
  end;

  in_addr = TInAddr;

  PSockAddrIn = ^TSockAddrIn;

  TSockAddrIn = record
    case integer of
      0:
        (sin_family: Word;
          sin_port: Word;
          sin_addr: TInAddr;
          sin_zero: array [0 .. 7] of Char);
      1:
        (sa_family: Word;
          sa_data: array [0 .. 13] of Char)
  end;

  sockaddr_in = TSockAddrIn;

  ppcap_t = ^pcap_t;
  pcap_t = integer;

  pbpf_u_int32 = ^bpf_u_int32;
  bpf_u_int32 = integer; // gilgil temp 2003.07.20
  long = integer;
  // u_int = LongWord;
  ppchar = ^pAnsichar; // gilgil temp 2003.07.20

  ppcap_addr_t = ^pcap_addr_t;

  pcap_addr_t = packed record
    next: ppcap_addr_t;
    addr: PSockAddrIn; { address }
    netmask: PSockAddrIn; { netmask for that address }
    broadaddr: PSockAddrIn; { broadcast address for that address }
    dstaddr: PSockAddrIn; { P2P destination address for that address }
  end;

  ppcap_if_t = ^pcap_if_t;
  pppcap_if_t = ^ppcap_if_t;

  pcap_if_t = packed record
    next: ppcap_if_t;
    name: pAnsichar;
    description: pAnsichar;
    address: ppcap_addr_t;
    flags: bpf_u_int32;
  end;

  ppkt_header = ^pkt_header;
  pkt_header = integer; // gilgil temp 2003.07.20

  ppcap_rmtauth = ^pcap_rmtauth;

  pcap_rmtauth = packed record
    type_: integer;
    username: pAnsichar;
    password: pAnsichar;
  end;

  timeval = packed record
    tv_sec: long;
    tv_usec: long;
  end;

  ppcap_pkthdr = ^pcap_pkthdr;

  pcap_pkthdr = packed record
    ts: timeval;
    caplen: bpf_u_int32;
    len: bpf_u_int32 end;

    ppcap_dumper_t = ^pcap_dumper_t;
    pcap_dumper_t = integer; // gilgil temp 2003.07.26

    pcap_handler =
    procedure(p: pAnsichar; header: ppkt_header; data: pAnsichar);
    cdecl;

    // ----------------------------------------------------------------------------
    // Function Definition
    // ----------------------------------------------------------------------------

  var
    pcap_findalldevs: function(alldevs: pppcap_if_t; errbuf: pAnsichar)
      : integer; cdecl;
    pcap_freealldevs: procedure(alldevs: ppcap_if_t); cdecl;
    pcap_open_live: function(device: pAnsichar; snaplen: integer;
      promisc: integer; to_ms: integer; ebuf: pAnsichar): ppcap_t; cdecl;
    pcap_close: procedure(p: ppcap_t); cdecl;
    pcap_loop: function(p: ppcap_t; cnt: integer; ppcap_handler: pointer;
      user: pAnsichar): integer; cdecl;
    pcap_next_ex: function(p: ppcap_t; pkt_header: ppcap_pkthdr;
      pkt_data: ppchar): integer; cdecl;
    pcap_lookupnet: function(device: pAnsichar; netp: pbpf_u_int32;
      maskp: pbpf_u_int32; errbuf: pAnsichar): integer; cdecl;
    pcap_compile: function(p: ppcap_t; fp: pbpf_program; str: pAnsichar;
      optimize: integer; netmask: bpf_u_int32): integer; cdecl;
    pcap_setfilter: function(p: ppcap_t; fp: pbpf_program): integer; cdecl;
    pcap_geterr: function(p: ppcap_t): pAnsichar; cdecl;
    pcap_dump_open: function(p: ppcap_t; fname: pAnsichar)
      : ppcap_dumper_t; cdecl;
    pcap_dump: procedure(p: ppcap_dumper_t; h: ppcap_pkthdr;
      sp: pAnsichar); cdecl;
    pcap_dump_close: procedure(p: ppcap_dumper_t); cdecl;
    pcap_sendpacket: function(p: ppcap_t; buf: pAnsichar; size: integer)
      : integer; cdecl;
    pcap_lib_version: function(): pAnsichar; cdecl;

implementation

end.