{"id":679,"date":"2022-10-26T14:49:14","date_gmt":"2022-10-26T06:49:14","guid":{"rendered":"https:\/\/blog.cclo.idv.tw\/?p=679"},"modified":"2023-05-01T21:24:27","modified_gmt":"2023-05-01T13:24:27","slug":"%e7%bf%bb%e8%ad%af-eric-%e7%9a%84-bstr-%e5%ae%8c%e5%85%a8%e6%94%bb%e7%95%a5","status":"publish","type":"post","link":"https:\/\/blog.cclo.idv.tw\/?p=679","title":{"rendered":"[\u7ffb\u8b6f] Eric \u7684 BSTR \u5b8c\u5168\u653b\u7565"},"content":{"rendered":"

\uff08\u539f\u6587\u51fa\u8655\uff1ahttps:\/\/ericlippert.com\/2003\/09\/12\/erics-complete-guide-to-bstr-semantics\/<\/a>\uff09<\/p>\n

\n

\u5982\u679c\u4f60\u66fe\u7d93\u7528 C \u6216 C++ \u5beb\u904e\u4efb\u4f55\u4f7f\u7528\u5230 COM \u7269\u4ef6\u7684\u7a0b\u5f0f\uff0c\u4f60\u4e00\u5b9a\u770b\u904e\u985e\u4f3c\u7684\u7a0b\u5f0f\u78bc\uff1a<\/p>\n

STDMETHODIMP CFoo:Bar(BSTR bstrABC)\n{ ... }<\/code><\/pre>\n
\u9019\u500b BSTR<\/code> \u5230\u5e95\u662f\u4e09\u5c0f\uff1f\u5b83\u548c WCHAR*<\/code> \u53c8\u6709\u4ec0\u9ebc\u5340\u5225\uff1f<\/strong><\/p>\n
\u50cf C \u6216 C++ \u9019\u7a2e\u4f4e\u968e\u8a9e\u8a00\uff0c\u4f60\u6709\u7d55\u5c0d\u7684\u81ea\u7531\u53ef\u4ee5\u6c7a\u5b9a\uff1a\u7a76\u7adf\u8981\u7528\u4ec0\u9ebc\u65b9\u5f0f\u5be6\u4f5c\u67d0\u7a2e\u6982\u5ff5\u3002Unicode \u5b57\u4e32\u5c31\u662f\u500b\u7d55\u4f73\u7bc4\u4f8b\u3002\u7528 C++ \u4f86\u8868\u793a\u9577\u5ea6\u70ba n \u500b\u5b57\u5143\u7684 Unicode \u5b57\u4e32\u7684\u6a19\u6e96\u65b9\u6cd5\u662f\u4e00\u500b\u6307\u5411 2 * (n + 1) bytes \u8a18\u61b6\u9ad4\u7a7a\u9593\u7684\u6307\u6a19\u3002\u9019\u584a\u7a7a\u9593\u4e2d\u7684\u524d 2 * n bytes \u662f\u7528\u4f86\u8868\u793a UTF-16 \u7de8\u78bc\u5b57\u5143\u7684\u7121\u865f\u77ed\u6574\u6578 (unsigned short integers)\uff0c\u6700\u5f8c 2 \u500b bytes \u7684\u5167\u5bb9\u5247\u662f 0\uff0c\u7528\u4f86\u8868\u793a\u5b57\u4e32\u7684\u7d50\u5c3e\u3002<\/p>\n
<\/div>\n
\u70ba\u4e86\u8868\u793a\u4e0a\u7684\u65b9\u4fbf\uff0c\u6211\u5011\u5229\u7528\u300c\u5308\u7259\u5229\u8868\u793a\u6cd5\u300d\uff0c\u7a31\u547c\u9019\u6a23\u7684\u602a\u7269\u70ba PWSZ<\/code>\uff0c\u610f\u5373\u300c\u6307\u5411\u5bec\u5b57\u5143\u7684\u6307\u6a19\uff0c\u4ee5\u96f6\u7d50\u5c3e (Pointer to Wide-character String, Zero-terminated)\u300d\u3002\u4ee5 C++ \u7684\u578b\u5225\u7cfb\u7d71\u4f86\u8aaa\uff0cPWSZ<\/code> \u5c31\u662f\u4e00\u500b unsigned short *<\/code>\u3002<\/p>\n
COM \u5132\u5b58\u5b57\u4e32\u8cc7\u6599\u7684\u65b9\u6cd5\u6709\u4e00\u9ede\u9ede\u4e0d\u540c\uff0c\u9019\u7a2e\u65b9\u6cd5\u548c\u524d\u8ff0\u7684\u65b9\u6cd5\u985e\u4f3c\uff0c\u4ee5\u78ba\u4fdd\u7528 PWSZ<\/code> \u65b9\u5f0f\u8655\u7406\u5b57\u4e32\u7684\u7a0b\u5f0f\u78bc\u3001\u4ee5\u53ca\u63d0\u4f9b COM \u683c\u5f0f\u5b57\u4e32\u7684\u7a0b\u5f0f\u78bc\u4e4b\u9593\uff0c\u53ef\u4ee5\u826f\u597d\u6e9d\u901a\u3002\u4e0d\u5e78\u7684\u662f\uff0c\u9019\u5169\u8005\u4e4b\u9593\u7684\u5dee\u7570\u4e26\u4e0d\u5c0f\u3002\u5982\u679c\u4f60\u4e0d\u5920\u5c0f\u5fc3\uff0c\u6216\u662f\u4e0d\u4e86\u89e3\u9019\u4e9b\u5dee\u7570\u7684\u8a71\uff0c\u9019\u4e9b\u7d30\u5fae\u7684\u5dee\u7570\u5c31\u6703\u5c0e\u81f4\u4ee4\u4eba\u56f0\u64fe\u7684\u932f\u8aa4\u3002<\/p>\n
COM \u7684\u7a0b\u5f0f\u78bc\u4f7f\u7528 BSTR<\/code> \u4f86\u5132\u5b58 Unicode \u5b57\u4e32\u3002BSTR<\/code> \u662f "Basic STRing" \u7684\u7e2e\u5beb\u3002\u4e4b\u6240\u4ee5\u9019\u9ebc\u547d\u540d\uff0c\u662f\u56e0\u70ba\u9019\u7a2e\u5132\u5b58\u5b57\u4e32\u7684\u65b9\u6cd5\u662f\u70ba\u4e86 OLE Automation \u958b\u767c\u7684\uff0c\u800c OLE Automation \u7576\u6642\u53c8\u662f\u56e0\u70ba Visual Basic \u8a9e\u8a00\u5f15\u64ce\u7684\u958b\u767c\u800c\u958b\u59cb\u7684\u3002\uff08\u8b6f\u8a3b\uff1a\u6240\u4ee5 BSTR<\/code> \u7684 "Basic" \u6307\u7684\u5c31\u662f "Visual Basic"\uff0c\u800c\u4e0d\u662f\u300c\u57fa\u672c\u300d\u3002\uff09<\/p>\n
\u5f9e\u7de8\u8b6f\u5668\u7684\u89d2\u5ea6\u4f86\u770b\uff0cBSTR<\/code> \u4e5f\u662f\u4e00\u500b unsigned short *<\/code>\u3002\u5982\u679c\u4f60\u5728\u9700\u8981 PWSZ<\/code> \u7684\u5730\u65b9\u4f7f\u7528 BSTR<\/code>\uff0c\u7de8\u8b6f\u5668\u4e0d\u6703\u5728\u610f\uff0c\u53cd\u4e4b\u4ea6\u7136\u3002\u4f46\u9019\u4e26\u4e0d\u4ee3\u8868\u4f60\u53ef\u4ee5\u8086\u7121\u5fcc\u619a\u5730\u9019\u9ebc\u505a\uff01\u5982\u679c\u5169\u8005\u5b8c\u5168\u4e00\u6a23\uff0c\u90a3\u5c31\u4e0d\u9700\u8981\u5206\u5225\u7528\u4e0d\u540c\u7684\u540d\u7a31\u8868\u793a\u4e86\u3002\u9019\u5169\u7a2e\u578b\u5225\u4e4b\u9593\u6709\u8a31\u591a\u4e0d\u540c\u4e4b\u8655\u3002<\/p>\n
\u5728\u5927\u90e8\u4efd\u7684\u60c5\u6cc1\u4e0b\uff0cBSTR<\/code> \u53ef\u4ee5\u88ab\u7576\u6210 PWSZ<\/code> \u4f86\u4f7f\u7528\u3002\u4f46 PWSZ<\/code> \u53ea\u6709\u5728\u6975\u5c11\u6578\u7684\u60c5\u6cc1\u4e0b\uff0c\u624d\u80fd\u88ab\u7576\u6210 BSTR<\/code> \u4f86\u4f7f\u7528\u3002<\/strong><\/p>\n
\u8b93\u6211\u5148\u5217\u51fa\u9019\u5169\u8005\u4e4b\u9593\u7684\u5340\u5225\uff0c\u540c\u6642\u8a73\u7d30\u8aaa\u660e\u6bcf\u4e00\u9ede\u3002<\/p>\n
    \n
  1. \u5c0d\u65bc BSTR<\/code>\uff0cNULL<\/code> \u548c ""<\/code> \u5728\u8a9e\u610f\u4e0a\u5fc5\u9808\u5b8c\u5168\u76f8\u540c\u3002\u800c\u5c0d\u65bc PWSZ<\/code>\uff0c\u9019\u5169\u8005\u7684\u8a9e\u610f\u901a\u5e38\u662f\u4e0d\u540c\u7684\u3002<\/li>\n
  2. BSTR<\/code> \u7269\u4ef6\u5fc5\u9808\u4ee5 SysAlloc<\/code> \u5bb6\u65cf\u7684\u51fd\u5f0f\u4f86\u914d\u7f6e\/\u91cb\u653e\u8a18\u61b6\u9ad4\u3002PWSZ<\/code> \u7269\u4ef6\u5247\u53ef\u4ee5\u662f stack \u4e0a\u81ea\u52d5\u914d\u7f6e\u7684\u5132\u5b58\u7a7a\u9593\uff0c\u6216\u662f\u4f7f\u7528 malloc<\/code>\u3001new<\/code>\u3001LocalAlloc<\/code> \u6216\u4efb\u4f55\u5176\u4ed6\u7684\u8a18\u61b6\u9ad4\u914d\u7f6e\u51fd\u5f0f\u4f86\u914d\u7f6e\u8a18\u61b6\u9ad4\u3002<\/li>\n
  3. BSTR<\/code> \u5b57\u4e32\u7684\u9577\u5ea6\u662f\u56fa\u5b9a\u7684\u3002PWSZ<\/code> \u7684\u9577\u5ea6\u53ef\u4ee5\u662f\u4efb\u610f\u503c\uff0c\u53ea\u53d7\u5230\u5176\u6307\u5411\u7684 buffer \u7684\u6709\u6548\u8a18\u61b6\u9ad4\u5927\u5c0f\u9650\u5236\u3002<\/li>\n
  4. BSTR<\/code> \u6c38\u9060\u6307\u5411 buffer \u4e2d\u7684\u7b2c\u4e00\u500b\u6709\u6548\u5b57\u5143\u3002PWSZ<\/code> \u53ef\u80fd\u662f\u500b\u6307\u5411\u5b57\u4e32 buffer \u4e2d\u9593\u6216\u7d50\u675f\u4f4d\u5740\u7684\u6307\u6a19\u3002<\/li>\n
  5. \u7576\u4f60\u914d\u7f6e\u4e86 n bytes \u7d66 BSTR<\/code> \u6642\uff0c\u9019\u500b\u5b57\u4e32\u53ef\u4ee5\u5b58\u653e n\/2 \u500b\u5bec\u5b57\u5143\u3002\u7576\u4f60\u914d\u7f6e\u4e86 n bytes \u7d66 PWSZ<\/code> \u6642\uff0c\u4f60\u53ef\u4ee5\u5b58\u653e n \/ 2 - 1 \u500b\u5b57\u5143\uff0c\u56e0\u70ba\u4f60\u5fc5\u9808\u4fdd\u7559\u6700\u5f8c\u4e00\u500b\u5b57\u5143\u7684\u7a7a\u9593\u5b58\u653e\u8868\u793a\u7d50\u5c3e\u7684\u96f6\u5b57\u5143\u3002<\/li>\n
  6. BSTR<\/code> \u5b87\u4e32\u4e2d\u53ef\u80fd\u5305\u542b\u4efb\u4f55\u7684 Unicode \u8cc7\u6599\uff0c\u5305\u62ec\u96f6\u5b57\u5143\u3002PWSZ<\/code> \u9664\u4e86\u7d50\u5c3e\u7684 \u96f6\u5b57\u5143\u4ee5\u5916\uff0c\u4e0d\u5f97\u5305\u542b\u4efb\u4f55\u7684\u96f6\u5b57\u5143\u3002\u4e0d\u7ba1\u662f BSTR<\/code> \u9084\u662f PWSZ<\/code>\uff0c\u5728\u6700\u5f8c\u4e00\u500b\u6709\u6548\u5b57\u5143\u7684\u5f8c\u9762\uff0c\u90fd\u6703\u6709\u4e00\u500b\u96f6\u5b57\u5143\uff1b\u4f46\u662f\u5728 BSTR<\/code> \u4e2d\uff0c\u96f6\u5b57\u5143\u4e5f\u53ef\u4ee5\u662f\u6709\u6548\u5b57\u5143\u3002<\/li>\n
  7. BSTR<\/code> \u7684 byte \u9577\u5ea6\u5176\u5be6\u53ef\u4ee5\u662f\u5947\u6578 -- \u5b83\u53ef\u4ee5\u7528\u4f86\u50b3\u905e\u4e8c\u9032\u4f4d\u8cc7\u6599\uff0c\u96d6\u7136\u6211\u4e0d\u5efa\u8b70\u9019\u9ebc\u505a\u3002PWSZ<\/code> \u7684 byte \u9577\u5ea6\u5247\u4e00\u5b9a\u662f\u5076\u6578\uff0c\u800c\u4e14\u53ea\u80fd\u7528\u4f86\u5132\u5b58 Unicode \u5b57\u4e32\u3002<\/li>\n<\/ol>\n
    \u591a\u5e74\u4f86\uff0c\u6211\u767c\u73fe\u3001\u4fee\u5fa9\u4e86\u7121\u6578\u7684\u932f\u8aa4\uff0c\u90fd\u662f\u56e0\u70ba\u7a0b\u5f0f\u78bc\u539f\u4f5c\u8005\u5047\u8a2d PWSZ<\/code> \u53ef\u4ee5\u7576\u4f5c BSTR<\/code>\uff08\u6216\u53cd\u904e\u4f86\uff09\u4f7f\u7528\uff0c\u9032\u800c\u9055\u53cd\u4e86\u4e0a\u8ff0\u7684\u5dee\u7570\u4e4b\u4e00\u3002\u8b93\u6211\u5011\u4ed4\u7d30\u4f86\u8a0e\u8ad6\u9019\u4e9b\u5dee\u7570\u5427\uff1a<\/p>\n
      \n
    1. \n
      \u5982\u679c\u4f60\u5beb\u7684\u51fd\u5f0f\u63a5\u53d7\u4e00\u500b\u578b\u5225\u70ba BSTR<\/code> \u7684\u53c3\u6578\uff0c\u90a3\u9ebc\u4f60\u5c31\u5fc5\u9808\u63a5\u53d7 NULL<\/code> \u662f\u500b\u6709\u6548\u7684 BSTR<\/code> \u5b57\u4e32\uff0c\u800c\u4e14\u628a\u5b83\u8996\u70ba\u6307\u5411\u7a7a\u5b57\u4e32\uff08\u5373\u9577\u5ea6\u70ba 0 \u7684\u5b57\u4e32\uff09\u7684\u6307\u6a19\u3002COM \u7167\u8457\u9019\u500b\u898f\u5247\u8d70\uff0c\u800c\u4e14 Visual Basic \u548c VBScript \u4e5f\u662f\u5982\u6b64\u3002\u6240\u4ee5\u5982\u679c\u4f60\u60f3\u8ddf\u5225\u4eba\u4e00\u8d77\u73a9\uff0c\u4f60\u5c31\u5f97\u9075\u5b88\u9019\u500b\u904a\u6232\u898f\u5247\u3002\u5982\u679c VB \u4e2d\u7684\u67d0\u500b\u5b57\u4e32\u8b8a\u6578\u6070\u597d\u662f\u7a7a\u5b57\u4e32\uff0c\u90a3\u9ebc VB \u50b3\u9032\u4f86\u7684\u53c3\u6578\u5c31\u6709\u53ef\u80fd\u662f NULL<\/code>\uff0c\u4e5f\u6709\u53ef\u80fd\u662f\u6307\u5411\u7a7a\u5b57\u4e32\u7684\u6307\u6a19 -- \u5b8c\u5168\u8996\u8a72 VB \u7a0b\u5f0f\u7684\u5167\u90e8\u8655\u7406\u65b9\u5f0f\u800c\u5b9a\u3002\u5c0d\u65bc\u4f7f\u7528 PWSZ<\/code> \u7684\u7a0b\u5f0f\u78bc\u4f86\u8aaa\uff0c\u901a\u5e38\u4e0d\u662f\u9019\u6a23\u7684\uff1a\u901a\u5e38 NULL<\/code> \u6307\u7684\u662f\u300c\u9019\u500b\u5b57\u4e32\u503c\u4e0d\u5b58\u5728\u300d\uff0c\u800c\u4e0d\u662f\u7b49\u540c\u65bc\u7a7a\u5b57\u4e32\u3002
      \n\u5728 COM \u4e2d\uff0c\u5982\u679c\u4f60\u6709\u4e00\u500b\u300c\u53ef\u80fd\u5b58\u5728\u3001\u4e5f\u53ef\u80fd\u4e0d\u5b58\u5728\u300d\u7684\u8cc7\u6599\uff0c\u90a3\u9ebc\u4f60\u61c9\u8a72\u8981\u7528 VARIANT<\/code> \u4f86\u5132\u5b58\uff0c\u7136\u5f8c\u7528 VT_NULL<\/code> \u4ee3\u8868\u6578\u5b57\u4e0d\u5b58\u5728\uff1b\u800c\u4e0d\u662f\u5c07 NULL<\/code> \u89e3\u8b6f\u70ba\u7a7a\u5b57\u4e32\u4ee5\u5916\u7684\u610f\u7fa9\u3002<\/p>\n<\/li>\n
    2. \n
      BSTR<\/code> \u5b57\u4e32\u5fc5\u9808\u8981\u4f7f\u7528 SysAllocString<\/code>\u3001SysAllocStringLen<\/code>\u3001SysFreeString<\/code> \u7b49\u51fd\u5f0f\u4f86\u5206\u914d\u3001\u91cb\u653e\u8a18\u61b6\u9ad4\u3002\u5e95\u5c64\u7684\u8a18\u61b6\u9ad4\u662f\u7531\u4f5c\u696d\u7cfb\u7d71\u5feb\u53d6\u7684\uff0c\u82e5\u662f\u5c0d BSTR<\/code> \u4f7f\u7528 free<\/code> \u6216\u662f delete<\/code> \u6703\u9020\u6210 heap \u640d\u6bc0\u7684\u56b4\u91cd\u932f\u8aa4\u3002\u540c\u7406\uff0c\u4f7f\u7528 malloc<\/code> \u6216 new<\/code> \u4f86\u914d\u7f6e buffer \u7a7a\u9593\u3001\u518d\u6307\u6d3e\u7d66 BSTR<\/code> \u7269\u4ef6\uff0c\u4e5f\u4e00\u6a23\u6703\u9020\u6210\u932f\u8aa4\u3002\u4f5c\u696d\u7cfb\u7d71\u5167\u90e8\u7684\u7a0b\u5f0f\u78bc\u5c0d BSTR<\/code> \u5728\u8a18\u61b6\u9ad4\u4e2d\u7684\u4f48\u5c40\u505a\u4e86\u5047\u8a2d\uff0c\u5617\u8a66\u53bb\u6a21\u64ec\u9019\u6a23\u7684\u4f48\u5c40\u662f\u4e0d\u667a\u4e4b\u8209\u3002\u76f8\u5c0d\u4f86\u8aaa\uff0cPWSZ<\/code> \u5247\u53ef\u4ee5\u4f7f\u7528\u4efb\u4f55\u7684\u5206\u914d\u65b9\u5f0f\u4f86\u914d\u7f6e\u8a18\u61b6\u9ad4\uff0c\u4e5f\u53ef\u4ee5\u76f4\u63a5\u914d\u7f6e\u5728 stack \u7a7a\u9593\u4e2d\u3002<\/p>\n<\/li>\n
    3. \n
      \u5728 BSTR<\/code> \u4e2d\uff0c\u5b57\u5143\u7684\u6578\u91cf\u662f\u56fa\u5b9a\u7684\u3002\u4e00\u500b\u9577\u5ea6\u70ba 10 bytes \u7684 BSTR<\/code>\uff0c\u88e1\u9762\u5305\u542b\u4e86 5 \u500b UTF-16 \u7684\u5b57\u5143\uff0c\u5c31\u9019\u6a23\u3002\u5c31\u7b97\u9019\u4e9b\u5b57\u5143\u90fd\u662f 0\uff0c\u5b83\u9084\u662f\u5305\u542b\u4e86 5 \u500b<\/em> \u96f6\u5b57\u5143\u3002\u53e6\u4e00\u65b9\u9762\uff0cPWSZ<\/code> \u53ef\u4ee5\u5305\u542b\u300c\u4e0d\u8d85\u904e buffer \u5927\u5c0f\u300d\u7684\u5b57\u5143\u6578\uff1a<\/p>\n
      WCHAR pwszBuf[101];\npwszBuf[0] = 'X';\npwszBuf[1] = '';<\/code><\/pre>\n
      \u73fe\u5728 pwszBuf<\/code> \u662f\u500b\u5305\u542b\u6709\u4e00\u500b\u5b57\u5143\u7684\u5b57\u4e32\uff0c\u800c\u4e14\u53ef\u4ee5\u6700\u591a\u589e\u9577\u5230 100 \u500b\u5b57\u5143\uff0c\u6216\u662f\u7e2e\u77ed\u6210 0 \u500b\u5b57\u5143\u7684\u7a7a\u5b57\u4e32\u3002<\/p>\n<\/li>\n
    4. \n
      BSTR<\/code> \u6307\u6a19\u6c38\u9060\u6307\u5411 buffer \u4e2d\u7684\u7b2c\u4e00\u500b\u6709\u6548\u5b57\u5143\u3002\u4e0b\u9762\u9019\u6a23\u505a\u662f\u4e0d\u5408\u6cd5\u7684\uff1a<\/p>\n
      BSTR bstrName = SysAllocString(L"John Doe");\nBSTR bstrLast = &bstrName[5]; \/\/ \u932f\u8aa4<\/code><\/pre>\n
      bstrLast<\/code> \u4e0d\u662f\u5408\u6cd5\u7684 BSTR<\/code>\u3002\u4f46\u5c0d PWSZ<\/code> \u4f86\u8aaa\uff0c\u9019\u9ebc\u505a\u662f\u5b8c\u5168\u5408\u6cd5\u7684\uff1a<\/p>\n
      WCHAR * pwszName = L"John Doe";\nWCHAR * pwszLast = &pwszName[5];<\/code><\/pre>\n<\/li>\n
    5. \n
      \u8acb\u53c3\u7167 (6)\u3002<\/p>\n<\/li>\n
    6. \n
      \u7576\u4f60\u4e86\u89e3 BSTR<\/code> \u5728\u8a18\u61b6\u9ad4\u4e2d\u7684\u4f48\u5c40\u5230\u5e95\u662f\u600e\u6a23\u4e4b\u5f8c\uff0c\u5c31\u80fd\u66f4\u6e05\u695a\u70ba\u4ec0\u9ebc\u6703\u6709\u4e0a\u8ff0\u7684\u90a3\u4e9b\u9650\u5236\uff0c\u540c\u6642\u4e5f\u80fd\u89e3\u91cb\u70ba\u4ec0\u9ebc\u914d\u7f6e\u4e86 n \u500b\u5b57\u5143\u7684 BSTR<\/code> \u53ef\u4ee5\u5b58\u653e n \u500b\u5b57\u5143\uff0c\u800c\u4e0d\u662f\u50cf PWSZ<\/code> \u4e00\u6a23\u53ea\u80fd\u653e n - 1 \u500b\u5b57\u5143\u3002\u7576\u4f60\u547c\u53eb SysAllocString(L"ABCDE")<\/code> \u6642\uff0c\u4f5c\u696d\u7cfb\u7d71\u5176\u5be6\u6703\u5e6b\u4f60\u914d\u7f6e 16 bytes<\/em> \u7684\u7a7a\u9593\u3002\u6700\u524d\u9762\u7684 4 bytes \u662f\u4e00\u500b 32-bit \u7684\u6574\u6578\uff0c\u7528\u4f86\u8868\u793a\u300c\u9019\u500b\u5b57\u4e32\u4e2d\u7684\u6709\u6548 bytes \u6578\u91cf\u300d -- \u5728\u9019\u500b\u4f8b\u5b50\u4e2d\u6703\u88ab\u586b\u5165 10\u3002\u63a5\u4e0b\u4f86\u7684 10 \u500b bytes \u7684\u6240\u6709\u6b0a\u5c6c\u65bc\u547c\u53eb\u8005\uff0c\u800c\u5167\u5bb9\u5247\u6703\u662f\u900f\u904e\u914d\u7f6e\u51fd\u5f0f\u50b3\u5165\u7684\u8cc7\u6599\u3002\u6700\u5f8c\u7684\u5169\u500b bytes \u6703\u88ab\u586b\u5165 0\u3002\u7136\u5f8c\u4f60\u6703\u5f97\u5230\u4e00\u500b\u6307\u5411\u8cc7\u6599\uff08\u800c\u975e\u6a19\u982d\uff09\u7684\u6307\u6a19\u3002\uff08\u8b6f\u8a3b\uff1a\u793a\u610f\u5716\u5982\u4e0b\uff09<\/p>\n
      \"\"<\/p>\n
      \u9019\u7acb\u523b\u89e3\u91cb\u4e86\u5e7e\u500b\u95dc\u65bc BSTR<\/code> \u7684\u4e8b\u5be6\uff1a<\/p>\n
        \n
      • \u5b57\u4e32\u9577\u5ea6\u53ef\u4ee5\u7acb\u523b\u5f97\u77e5\u3002SysStringLen<\/code> \u4e26\u4e0d\u6703\u50cf wcslen<\/code> \u4e00\u6a23\u4e00\u500b\u5b57\u5143\u4e00\u500b\u5b57\u5143\u7b97\u5230\u96f6\u5b57\u5143\u3002\u5b83\u53ef\u4ee5\u76f4\u63a5\u8b80\u53d6\u6307\u6a19\u524d\u9762\u7684\u6574\u6578\uff0c\u7acb\u523b\u56de\u50b3\u3002<\/li>\n
      • \u9019\u4e5f\u662f\u70ba\u4ec0\u9ebc BSTR<\/code> \u6307\u6a19\u4e0d\u53ef\u4ee5\u6307\u5411\u53e6\u4e00\u500b BSTR<\/code> \u5b57\u4e32\u4e2d\u9593\u7684\u4efb\u610f\u4e00\u500b\u5b57\u5143\u3002\u56e0\u70ba\u9019\u500b\u6307\u6a19\u7684\u524d\u9762\u4e0d\u6703\u662f\u5b57\u4e32\u7684\u9577\u5ea6\u3002<\/li>\n
      • BSTR<\/code> \u53ef\u4ee5\u88ab\u7576\u6210 PWSZ<\/code> \u4f7f\u7528\uff0c\u56e0\u70ba\u914d\u7f6e\u51fd\u5f0f\u4e00\u5b9a\u6703\u5e6b\u4f60\u5728\u5b57\u4e32\u7684\u7d50\u5c3e\u52a0\u4e0a\u4e00\u500b\u96f6\u5b57\u5143\u3002\u8eab\u70ba\u547c\u53eb\u8005\u7684\u4f60\uff0c\u4e0d\u9700\u8981\u64d4\u5fc3\u662f\u5426\u914d\u7f6e\u4e86\u8db3\u5920\u653e\u7f6e\u96f6\u5b57\u5143\u7684\u8a18\u61b6\u9ad4\u3002\u5982\u679c\u4f60\u9700\u8981 5 \u500b\u5b57\u5143\u9577\u7684\u5b57\u4e32\uff0c\u76f4\u63a5\u8ddf\u914d\u7f6e\u51fd\u5f0f\u8981\u6c42 5 \u500b\u5b57\u5143\u5c31\u597d\u3002<\/li>\n
      • \u9019\u4e5f\u662f\u70ba\u4ec0\u9ebc BSTR<\/code> \u5fc5\u9808\u4f7f\u7528 SysAlloc<\/code> \u7cfb\u5217\u7684\u51fd\u5f0f\u4f86\u914d\u7f6e\/\u91cb\u653e\u3002\u53ea\u6709\u9019\u51fd\u5f0f\u624d\u80fd\u5b8c\u5168\u4e86\u89e3\u9019\u4e9b\u5e55\u5f8c\u7684\u7d30\u7bc0\u3002<\/li>\n<\/ul>\n<\/li>\n
      • \n
        \u56e0\u70ba BSTR<\/code> \u7684 bytes \u9577\u5ea6\u662f\u5df2\u77e5\u7684\uff0c\u6240\u4ee5\u4e0d\u9700\u8981\u4f7f\u7528\u300c\u96f6\u5b57\u5143\u4ee3\u8868\u5b57\u4e32\u7d50\u675f\u300d\u9019\u6a23\u7684\u6163\u4f8b\u3002\u56e0\u6b64\uff0c\u5728 BSTR<\/code> \u4e2d\uff0c\u96f6\u5b57\u5143\u662f\u5408\u6cd5\u7684\u5b57\u5143\u3002\u9019\u8868\u793a BSTR<\/code> \u53ef\u4ee5\u5305\u542b\u4efb\u610f\u7684\u8cc7\u6599\uff0c\u8868\u62ec\u4e8c\u9032\u5236\u6620\u50cf\u8cc7\u6599\u3002\u56e0\u70ba\u9019\u500b\u539f\u56e0\uff0cBSTR<\/code> \u9664\u4e86\u53ef\u4ee5\u8655\u7406\u5b57\u4e32\u8cc7\u6599\u5916\uff0c\u9084\u5e38\u88ab\u7576\u6210\u4e00\u7a2e\u8655\u7406\u4e8c\u9032\u4f4d\u8cc7\u6599\u7684\u65b9\u4fbf\u65b9\u6cd5\u3002\u9019\u610f\u5473\u8457\u5728\u67d0\u4e9b\u7279\u6b8a\u7684\u60c5\u6cc1\u4e0b\uff0c\u5b83\u7684\u9577\u5ea6\u53ef\u80fd\u6703\u662f\u5947\u6578\u3002\u9019\u7a2e\u60c5\u6cc1\u5f88\u5c11\u898b\uff0c\u4f46\u4e0d\u662f\u5b8c\u5168\u4e0d\u53ef\u80fd\u767c\u751f\uff0c\u4f60\u5f97\u7279\u5225\u6ce8\u610f\u3002\u6211\u5efa\u8b70\u4e0d\u8981\u9019\u9ebc\u505a\uff0c\u4f46\u4f60\u9084\u662f\u6709\u53ef\u80fd\u78b0\u5230\u3002<\/p>\n<\/li>\n<\/ol>\n
        \u547c\uff0c\u7d42\u65bc\uff01\u7e3d\u7d50\u4f86\u8aaa\uff0c\u9019\u61c9\u8a72\u53ef\u4ee5\u89e3\u91cb\u70ba\u4ec0\u9ebc BSTR<\/code> \u901a\u5e38\u53ef\u4ee5\u7576\u6210 PWSZ<\/code> \u4f7f\u7528\uff0c\u4f46 PWSZ<\/code> \u537b\u4e0d\u80fd\u7576\u505a BSTR<\/code> \u4f86\u7528\uff0c\u9664\u975e\u5b83\u771f\u7684\u662f BSTR<\/code>\u3002BSTR<\/code> \u53ea\u6709\u5728\u4e0b\u9762\u9019\u4e9b\u60c5\u6cc1\u4e0b\u624d \u4e0d\u80fd<\/strong> \u88ab\u7576\u6210 PWSZ<\/code> \u4f7f\u7528\uff1a<\/p>\n
          \n
        • \u7576 BSTR<\/code> \u70ba NULL<\/code> \u6642<\/li>\n
        • \u7576 BSTR<\/code> \u7684\u5167\u5bb9\u4e2d\u6709\u96f6\u5b57\u5143\u6642\uff08\u56e0\u70ba\u8655\u7406 PWSZ<\/code> \u7684\u7a0b\u5f0f\u78bc\u6703\u628a\u96f6\u5b57\u5143\u7576\u6210\u5b57\u4e32\u7d50\u5c3e\uff0c\u5c0e\u81f4\u7a0b\u5f0f\u6703\u8a8d\u70ba\u5b57\u4e32\u9577\u5ea6\u6bd4\u5be6\u969b\u4e0a\u7684\u77ed\uff09<\/li>\n
        • \u7576 BSTR<\/code> \u6240\u5305\u542b\u7684\u5176\u5be6\u4e0d\u662f\u5b57\u4e32\uff0c\u662f\u4e8c\u9032\u4f4d\u8cc7\u6599\u6642<\/li>\n<\/ul>\n
          \u552f\u4e00\u4e00\u500b\u53ef\u4ee5\u628a PWSZ<\/code> \u7576\u6210 BSTR<\/code> \u4f7f\u7528\u7684\u60c5\u6cc1\uff0c\u5c31\u662f\u90a3\u500b PWSZ<\/code> \u5176\u5be6 \u5c31\u662f<\/em> BSTR<\/code>\uff0c\u800c\u4e14\u7d93\u904e\u6b63\u78ba\u7684\u914d\u7f6e\u7a0b\u5f0f\u914d\u7f6e\u7a7a\u9593\u3002<\/p>\n
          \u5728\u6211\u81ea\u5df1\u5beb\u7684 C++ \u7a0b\u5f0f\u78bc\u4e2d\uff0c\u6211\u6703\u5f88\u5c0f\u5fc3\u5730\u4f7f\u7528\u5308\u7259\u5229\u547d\u540d\u6cd5\uff0c\u8a18\u9304\u6307\u6a19\u6240\u6307\u5411\u7684\u8cc7\u6599\u70ba\u4f55\uff0c\u4ee5\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u8aa4\u89e3\u3002\u4f7f\u7528\u5308\u7259\u5229\u547d\u540d\u6cd5\u6642\uff0c\u8981\u80fd\u6355\u6349\u5230\u8b8a\u6578\u7684\u8a9e\u610f\u8cc7\u8a0a\uff0c\u624d\u6703\u6709\u6700\u597d\u7684\u6548\u679c\u3002\u4ee5\u4e0b\u662f\u6211\u4f7f\u7528\u7684\u6163\u4f8b\uff1a<\/p>\n
            \n
          • bstr<\/code>\uff1a\u771f\u6b63\u7684 BSTR<\/code><\/li>\n
          • pwsz<\/code>\uff1a\u6307\u5411\u300c\u4ee5\u96f6\u5b57\u5143\u7d50\u5c3e\u300d\u7684\u5bec\u5b57\u5143\u5b57\u4e32\u7684\u6307\u6a19<\/li>\n
          • psz<\/code>\uff1a\u6307\u5411\u300c\u4ee5\u96f6\u5b57\u5143\u7d50\u5c3e\u300d\u7684\u7a84\u5b57\u5143\u5b57\u4e32\u7684\u6307\u6a19<\/li>\n
          • ch<\/code>\uff1a\u5b57\u5143<\/li>\n
          • pch<\/code>\uff1a\u6307\u5411\u4e00\u500b\u5bec\u5b57\u5143\u7684\u6307\u6a19<\/li>\n
          • cch<\/code>\uff1a\u5b57\u5143\u500b\u6578<\/li>\n
          • b<\/code>\uff1a\u4e00\u500b byte<\/li>\n
          • pb<\/code>\uff1a\u6307\u5411\u4e00\u500b byte \u7684\u6307\u6a19<\/li>\n
          • cb<\/code>\uff1abyte \u500b\u6578<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
            BSTR \u5728\u8655\u7406 COM \u5143\u4ef6\u6642\u5e38\u6703\u4f7f\u7528\u5230\u3002\u672c\u6587\u8a73\u7d30\u5730\u5206\u6790\u3001\u8aaa\u660e BSTR \u7684\u7709\u7709\u89d2\u89d2\u3002<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[13],"tags":[69,65,68,70],"table_tags":[],"class_list":["post-679","post","type-post","status-publish","format-standard","hentry","category--computer-science","tag-bstr","tag-c","tag-com","tag-windows-programming"],"aioseo_notices":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=\/wp\/v2\/posts\/679","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=679"}],"version-history":[{"count":12,"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=\/wp\/v2\/posts\/679\/revisions"}],"predecessor-version":[{"id":703,"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=\/wp\/v2\/posts\/679\/revisions\/703"}],"wp:attachment":[{"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=679"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=679"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=679"},{"taxonomy":"table_tags","embeddable":true,"href":"https:\/\/blog.cclo.idv.tw\/index.php?rest_route=%2Fwp%2Fv2%2Ftable_tags&post=679"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}