请教：IAR如何使一个未使用的函数不被优化掉

dalarang

例如在工程中有一个函数，我已将该函数指定编译到单独划分的一块FLASH地址中，但是想在工程中以函数指针指向该地址的方式来调用此函数。

而如果该函数没有被显性地调用，编译器会视为该函数未使用自动将其优化掉了，生成的二进制代码中实际是没有它的。

是否有什么办法可以让这个函数不被优化，无论有没有使用都可以自动生成。

ijlc1314

记得有个关键字好像是__root

security

你去帮助文档里面搜索一下 keep 关键字。

shangdawei

__root
The __root attribute can be used on either a function or a variable to ensure that, when the module containing the function or variable is linked, the function or variable is also included, whether or not it is referenced by the rest of the program.

By default only the part of the runtime library calling main and any interrupt vectors are root. All other functions and variables are included in the linked output only if they are referenced by the rest of the program.

The __root keyword is placed in front of the type, for example to place settings in non-volatile memory:

__root int settings[10];

The #pragma object_attribute directive can also be used. The following declaration is equivalent to the previous one:

#pragma object_attribute=__root
int settings[10];

Note: The __root keyword cannot be used in typedefs.

__root 关键字保证没有使用的函数或者变量也能够包含在目标代码中.

定义存放在__flash 空间的数据在程序编译时会自动生成代码嵌入到flash代码中，
对于程序没有使用也要求编译的数据（比如可以在代码中嵌入你的版本号，时间等）必须加关键字__root 限制。


Syntax --keep symbol
Parameters
symbol The name of the symbol to be treated as a root symbol

Description
Normally, the linker keeps a symbol only if it is needed by your application. Use this option to make a symbol always be included in the final application.

Project>Options>Linker>Input>Keep symbols

dalarang

谢谢楼上几位朋友的热心解答，经测试函数前加上__root关键字完美解决。

changer15309

#pragma optimize=none

dreamboy