对于qlibc的交叉编译。该文章的目标是编译一套aarch64 Linux Debian嵌入式版本上可以运行的版本库，接下来就开始趟坑。老套路，先把linux桌面版搞好，然后 移植到嵌入式Linux Debian 板子上。

1 qlibc简介

qLibc 这个项目就是提供一个通用的 C/C++ 库，包括所有种类的容器和常用工具函数。这里详细介绍下，主要分为两大部分：

核心API：

• Containers for Key/Value pairs
  • Tree Table --- in binary tree(left-leaning red-black tree) data structure.
  • Hash Table --- in hash-based data structure.
  • Static Hash Table --- in fixed size memory(array/mmapped/shared).
  • List Table --- in (doubly) linked-list data structure.
• Containers for Objects
  • List --- Doubly Linked List.
  • Vector --- implements a growable array of elements.
  • Queue --- FIFO(First In First Out) implementation.
  • Stack --- LIFO(Last In First Out) implementation.
• General utilities.
  • String --- string trimmer, modifier, replacer, case converter, pattern detectors, ...
  • I/O --- non-blocking I/O, stream reader/writer, ...
  • File --- file locking, file/directory hander, path correctors, ...
  • IPC, Semaphore Shared-memory
  • En/decoders --- Url en/decoder, Base64 en/decoder, Hex en/decoder, ...
  • Hashes --- Murmur hases, FNV hases, MD5 hashes, ...
  • Time --- time diff, time format converstion, ...

扩展API：

• Apache-style Configuration File Parser.
• INI-style Configuration File Parser.
• HTTP client.
• Rotating File Logger.
• Database(MySQL) interface.
• Token-Bucket

可以说qlibc的核心目的就是用于提供qlibc的基础API。

qlibc项目地址：GitHub qLibc Project

2 Linux 本地编译 & 交叉编译

2.1 Linux（ubuntu20.04）上qlibc的编译

qlibc通过configure文件来配置，流程如下：

$./configure
$make
$sudo make install

这里关于安装位置，可以通过--prefix=具体路径来设置。编译后生成库文件内容为：

├── libqlibc.a
├── libqlibcext.a
├── libqlibcext.so -> libqlibcext.so.2
├── libqlibcext.so.2
├── libqlibc.so -> libqlibc.so.2
└── libqlibc.so.2

2.2 aarch64交叉编译与移植

因为是用aarch64交叉编译，需要提前配置环境，安装如下软件：

sudo apt install binutils-aarch64-linux-gnu-dbg binutils-aarch64-linux-gnu cpp-aarch64-linux-gnu \
g++-10-aarch64-linux-gnu g++-9-aarch64-linux-gnu g++-aarch64-linux-gnu g++ \
gcc-10-aarch64-linux-gnu-base gcc-9-aarch64-linux-gnu-base gcc-aarch64-linux-gnu \
pkg-config-aarch64-linux-gnu qemu-efi-aarch64 gcc arch-test

在qlibc的目录中创建一个类似configure的配置文件aarch64-configure，内容为：

#!/bin/bash
 
ARCH="aarch64"
DEST_CPU="arm64"
HOST_OS="linux"
HOST_ARCH="x86_64"
 
export LINK_host="g++"
export CXX_host="g++"
export CC_host="gcc"
export AR_host="ar"
 
export CC=aarch64-linux-gnu-gcc
export CXX=aarch64-linux-gnu-g++
export LD=aarch64-linux-gnu-ld
export RANLIB=aarch64-linux-gnu-ranlib
export AR=aarch64-linux-gnu-ar
export AS=aarch64-linux-gnu-as
 
if [ -f "configure" ]; then
    ./configure --prefix=$PWD/out_aarch64_qlibc \
				--host=aarch64-linux-gnueabi \
fi

配置后接下来和桌面版linux类似：

$./aarch64-configure
$make
$sudo make install

这里执行后安装位置默认为：out_aarch64_qlibc。同样可以通过--prefix=具体路径来自定义设置。