Configure cross compilation tool chain and environment variables

Link to the original text ：https://blog.csdn.net/qq_56926420/article/details/122890366

1 Set the cross compilation tool chain

The cross compilation tool chain is used in Ubuntu Compile the application on the host , And these applications are in ARM And other platforms .
Setting the cross compilation tool is mainly to set PATH, ARCH and CROSS_COMPILE Three environment variables , The following describes the specific setting method .
Set this 3 There are several ways to create an environment variable , Choose any one of these methods , It is recommended to use “ permanent ” Methods . I use a variety of development boards when recording videos , So I always use... In videos “ Provisional entry into force ” Methods .

Library environment variable settings ：export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib

export LD_LIBRARY_PATH=/usr/local/X11/lib:$LD_LIBRARY_PATH/

1.1 permanent

If permanent modification is required , Please modify the user profile .
Be careful ： If you don't use vim command , You can use graphical editing tools , perform ：gedit ~/.bashrc
vim ~/.bashrc

(1)
Add or modify... At the end of the line , Add the following lines ( The first 3 Xing di 4 Act one line command )：

export ARCH=arm
export CROSS_COMPILE=arm-buildroot-linux-gnueabihf-
export PATH=$PATH:/home/book/100ask_imx6ull-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin
 After setting up , To execute   source  ~/.bashrc  Order it to take effect , This command is the environment variable that loads these settings .

After setting up , To execute source ~/.bashrc Order it to take effect , This command is the environment variable that loads these settings .

[email protected]:~$ source  ~/.bashrc
[email protected]:~$ arm-buildroot-linux-gnueabihf-gcc -v

1.2 Provisional entry into force

It can also be done manually “export” Command to set environment variables , This setting is only valid for the current terminal ( To open another terminal, you need to set it again ).
(1)
Perform the following 3 An order , The first 3 The order is very long , You need to include all copies of the fourth line ：

[email protected]:~$ export ARCH=arm
[email protected]:~$ export CROSS_COMPILE=arm-buildroot-linux-gnueabihf-
[email protected]:~$ export PATH=$PATH:/home/book/100ask_imx6ull-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin

1.3 Specify manually

First set up PATH environment variable , And then in make Specified at compile time ARCH framework CROSS_COMPILE Cross compile toolchain ( perform make Parameters specified during command , Only valid for the current command ; The next time to perform make You still need to specify those parameters again ).
(1) Example

[email protected]:~$ export PATH=$PATH:/home/book/100ask_imx6ull-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin
[email protected]:~$ make  ARCH=arm CROSS_COMPILE=arm-buildroot-linux-gnueabihf-

[email protected]:~$ export PATH=$PATH:/home/book/100ask_imx6ull-sdk/ToolChain/gcc-linaro-6.2.1-2016.11-x86_64_arm-linux-gnueabihf/bin
[email protected]:~$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- 

2 Test cross compilation tool chain

2.1 Test environment variables

[email protected]:~$ echo $ARCH
arm
[email protected]:~$ echo $CROSS_COMPILE
arm-buildroot-linux-gnueabihf-

2.2 Test cross compiler

Execute the following command , See the following figure for the results ：

[email protected]:~$ arm-buildroot-linux-gnueabihf-gcc -v

(1).
Configure environment variable 1 ：
Use export Order direct modification PATH Value ,
For example, after the cross compilation tool chain is installed ,

 Execute the following commands or execute 
export PATH=$PATH:/opt/hisi_linux/x86-arm/arm-himix100-linux/bin
 explain ：/opt/hisi_linux/x86-arm/arm-himix100-linux/bin Directory installed for compilation 

(2). Configure environment variable 2 ：
By modifying the ~/.bashrc File ：
Add or modify... At the end of the line , Add the following sentence

export PATH=$PATH:/opt/hisi_linux/x86-arm/arm-himix100-linux/bin
 After setting up , To execute  source  ~/.bashrc  Order it to take effect , This command is the environment variable that loads these settings .

Environment variable configuration method ：
Direct definition

export

Shell The configuration file
And Bash Shell The related configuration files mainly include

/etc/profile
~/.bash_profile
~/.bash_login
~/.profile
~/.bashrc
/etc/bashrc
/etc/bash.bashrc
/etc/profile.d/*.sh
Shell Execution order
/etc/profiles->/.profile(/.bash_profile、~/.bash_login)

Modify the configuration file
All users 、 Shared by all processes :/etc/bash.bashrc

A user 、 Shared by all processes :~/.bashrc

shell The effect of startup mode on variables
Son shell In process execution :/bin/bash Will create shell The child process and ./

Executing in the current process :source and .

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3 How to add cross compilation tool chain （toolchain） To environment variable ？（–sysroot route ）（ new ：ubuntu Configuration of environment variables of cross compilation tool chain ）

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