在开写之前，可以先看下这篇文章：Android NDK 如何缩减库的大小
iostream 会大幅增加大小,查了下代码, 只有读取文件这一个功能有用到iostream，以下面代码为例

void * FileUtils::readFileData(const std::string & filename, ssize_t * size) {
    std::ifstream in (filename, std::ifstream::ate | std::ifstream::binary);
    if (! in .is_open()) {
        throw std::runtime_error("file " + filename + " open error");
    }
    int fileSize = in .tellg();
    void * data = malloc(fileSize); in .seekg(0, std::ifstream::beg); in .read((char * ) data, fileSize); in .close();
    if (size) { *
        size = fileSize;
    }
    return data;
}

代码改为:

void * FileUtils::readFileData(const std::string & filename, ssize_t * size) {
    FILE * file = fopen(filename.c_str(), "rb");
    if (!file) {
        throw std::runtime_error("file " + filename + " open error");
    }
    struct stat info;
    if (stat(filename.c_str(), & info) != 0)
        throw std::runtime_error("get " + filename + " stat error");
    int fileSize = info.st_size;
    void * data = malloc(fileSize);
    fread(data, sizeof(void), fileSize, file);
    fclose(file);
    if (size) { *
        size = fileSize;
    }
    return data;
}

最后生成的.so文件将缩小300KB

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