{"id":238,"date":"2024-11-23T09:29:27","date_gmt":"2024-11-23T01:29:27","guid":{"rendered":"https:\/\/obagg.com\/index.php\/2024\/11\/23\/android-c-c-%e7%9f%a5%e8%af%86%e7%82%b9%e8%ae%b0%e5%bd%95\/"},"modified":"2024-11-23T09:29:27","modified_gmt":"2024-11-23T01:29:27","slug":"android-c-c-%e7%9f%a5%e8%af%86%e7%82%b9%e8%ae%b0%e5%bd%95","status":"publish","type":"post","link":"https:\/\/obagg.com\/index.php\/2024\/11\/23\/android-c-c-%e7%9f%a5%e8%af%86%e7%82%b9%e8%ae%b0%e5%bd%95\/","title":{"rendered":"Android C\/C++ \u77e5\u8bc6\u70b9\u8bb0\u5f55"},"content":{"rendered":"

\u76ee\u5f55<\/h3>\n
    \n
  1. ScopedUtfChars<\/li>\n
  2. os.open() flags\u542b\u4e49<\/li>\n<\/ol>\n

    ScopedUtfChars<\/h3>\n

    \u63d0\u4f9b\u5bf9 Java \u5b57\u7b26\u4e32\u7684 UTF \u5b57\u7b26\u7684\u53ea\u8bfb\u8bbf\u95ee\u7684\u667a\u80fd\u6307\u9488\u3002\u4e0e GetStringUTFChars \u4e0d\u540c\uff0c\u5982\u679c\u4f20\u9012\u4e00\u4e2a\u7a7a jstring\uff0c\u6211\u4eec\u5c06\u629b\u51fa NullPointerException \u800c\u4e0d\u662f\u4e2d\u6b62\uff0c\u5e76\u4e14 c_str \u5c06\u8fd4\u56de nullptr\u3002\u8fd9\u4f7f\u5f97\u6b63\u786e\u7684\u4e60\u60ef\u7528\u6cd5\u975e\u5e38\u7b80\u5355\uff1a<\/p>\n

    ScopedUtfChars name(env, java_name);\nif (name.c_str() == nullptr) {\n   return nullptr;\n}\n<\/code><\/pre>\n
    \u793a\u4f8b\uff1a<\/p>\n
    static bool dumpTraces(JNIEnv* env, jint pid, jstring fileName, jint timeoutSecs,\n                       DebuggerdDumpType dumpType) {\n    const ScopedUtfChars fileNameChars(env, fileName);\n    if (fileNameChars.c_str() == nullptr) {\n        return false;\n    }\n    ...\n}\n<\/code><\/pre>\n
    \u6e90\u7801\uff1a<\/p>\n
      ScopedUtfChars(JNIEnv* env, jstring s) : env_(env), string_(s) {\n    if (s == nullptr) {\n      utf_chars_ = nullptr;\n      jniThrowNullPointerException(env, nullptr);\n    } else {\n      utf_chars_ = env->GetStringUTFChars(s, nullptr);\n    }\n  }\n<\/code><\/pre>\n
    os.open() flags\u542b\u4e49<\/h3>\n