三方库里写死的，这个第三方库的作者可能没 上过《面向对象程序设计》，居然没有定义一 个公用的 Animal 基类并设一个 speak 为虚 函数。现在你抱怨也没有用，因为这个库是按 LGPL 协议开源的，你只能链接他，不能修改 他的源码，但你的老板却要求你把 speak 变 成一个虚函数！怎么样，是不是准备好递交辞 呈了？慢着，让万能的小彭老师来救你！ 类型擦除：还是以猫和狗为例 •

得可以获得两倍的性能。相似的 ，大多数多线程的应用不会比双核处理器的两倍快。他们应该比单核处理器运行的快，但 是性能毕竟不是线性增长。 • 为什么无法做到呢？首先，为了保证缓存一致性以及其他握手协议需要运行时间开销。在 今天，双核或者四核机器在多线程应用方面，其性能不见得的是单核机器的两倍或者四倍。 这一问题一直伴随 CPU 发展至今。 并发和并行的区别 • 运用多线程的方式和动机，一般分为两种。

name = "mosquitto" version = "1.4.15" description = "Open source message broker that implements the MQTT protocol" license = "EPL", "EDL" settings = "os", "arch", "compiler", "build_type" generators = "cmake" this recipe: Listing 26: conan-mosquitto_1.4.15.bb inherit conan DESCRIPTION = "An open source MQTT broker" LICENSE = "EPL-1.0" CONAN_PKG = "mosquitto/1.4.15@bincrafters/stable" This recipe will be

name = "mosquitto" version = "1.4.15" description = "Open source message broker that implements the MQTT protocol" license = "EPL", "EDL" settings = "os", "arch", "compiler", "build_type" generators = "cmake" this recipe: Listing 26: conan-mosquitto_1.4.15.bb inherit conan DESCRIPTION = "An open source MQTT broker" LICENSE = "EPL-1.0" CONAN_PKG = "mosquitto/1.4.15@bincrafters/stable" This recipe will be

name = "mosquitto" version = "1.4.15" description = "Open source message broker that implements the MQTT protocol" license = "EPL", "EDL" settings = "os", "arch", "compiler", "build_type" generators = "cmake" this recipe: Listing 26: conan-mosquitto_1.4.15.bb inherit conan DESCRIPTION = "An open source MQTT broker" LICENSE = "EPL-1.0" CONAN_PKG = "mosquitto/1.4.15@bincrafters/stable" This recipe will be

会采用当前硬件架构的字节序，比如在 x86 上就会变成小端字节序。 Java 这种虚拟机语言会采用大端字节序，因此在小端字节序的硬件上会比较低效，需要额外的字节序转换工作。 为了统一，互联网标准规定，协议包头中传输的数据类型（但凡是多个字节组成的）必须是大端字节序。 假如 x=0x01234567 ，则： int 类型对应的指针类型： int* • 指针，顾名思义，就是“指向”一个内存中的变量。

name = "mosquitto" version = "1.4.15" description = "Open source message broker that implements the MQTT protocol" license = "EPL", "EDL" settings = "os", "arch", "compiler", "build_type" generators = "cmake" this recipe: Listing 26: conan-mosquitto_1.4.15.bb inherit conan DESCRIPTION = "An open source MQTT broker" LICENSE = "EPL-1.0" CONAN_PKG = "mosquitto/1.4.15@bincrafters/stable" This recipe will be

name = "mosquitto" version = "1.4.15" description = "Open source message broker that implements the MQTT protocol" license = "EPL", "EDL" settings = "os", "arch", "compiler", "build_type" generators = "cmake" this recipe: Listing 26: conan-mosquitto_1.4.15.bb inherit conan DESCRIPTION = "An open source MQTT broker" LICENSE = "EPL-1.0" CONAN_PKG = "mosquitto/1.4.15@bincrafters/stable" This recipe will be

name = "mosquitto" version = "1.4.15" description = "Open source message broker that implements the MQTT protocol" license = "EPL", "EDL" settings = "os", "arch", "compiler", "build_type" generators = "cmake" this recipe: Listing 26: conan-mosquitto_1.4.15.bb inherit conan DESCRIPTION = "An open source MQTT broker" LICENSE = "EPL-1.0" CONAN_PKG = "mosquitto/1.4.15@bincrafters/stable" This recipe will be

name = "mosquitto" version = "1.4.15" description = "Open source message broker that implements the MQTT protocol" license = "EPL", "EDL" settings = "os", "arch", "compiler", "build_type" generators = "cmake" this recipe: Listing 26: conan-mosquitto_1.4.15.bb inherit conan DESCRIPTION = "An open source MQTT broker" LICENSE = "EPL-1.0" CONAN_PKG = "mosquitto/1.4.15@bincrafters/stable" This recipe will be