在C语言中,有强符号和弱符号,符号简单来说就是函数、变量的名字,对于全局(非局部、非static)的函数和变量,能不能重名是有一定规矩的,强、弱符号就是针对这些全局函数和变量来说的。 二 声明方法: 1 使用__attribute__((weak))修饰: //function declarationint__attribute__((weak)) power2(intx);//orint...
我们知道 C 语言是为了更好的构建跨平台操作系统 unix 而生的,理论上说,一份 C 源码只要在各个平台重新编译,就能轻松跨平台运行,但是在通常的嵌入式开发,尤其是mcu开发中,一份 C 源码却很难做到到处编译可用。 这并不是 C 语言本身出了问题,而是依赖项的问题。 为了方便理解,我们先预设一个应用场景: 我们编...
我们可以看到,在main.c和test.c都有一个global_var1,在main.c中的为强符号,在test.c中的为弱符号。因为在test.c中global_var1没有初始化,所以根据规则②得知:编译器选择main.c中的global_var1的值初始化那片内存。不要误认为在test.c中使用global_var1时是用的main.c中的global_var1,我之前错误得这样...
从上文中的RT-Thread代码可以看到,__weak在不同平台有不同面孔,有些甚至没有,这是因为__weak函数修饰符并不是C标准的里面的东西,这意味着: 并不是所有的编译器都支持__weak这个特性,有些小众的编译器还真就不支持,所以使用前请查询相关编译器是否支持。 __weak在所有支持的编译器中面貌长的也一样,详情还是...
Two weak C-H···N and C-H···F hydrogen bonds link the two subunits of the complex. Structural information on the hydrogen bridges has been obtained. The internal rotation of the CH3F subunit around its symmetry axis splits all rotational transitions into two (A and E) well resolved ...
Larvae were also raised at five constant temperatures for an estimation of the thermal performance curve, which showed that the thermal optimum for growth was 26.9 °C. Cannibalism was significantly positively correlated with initial body size variance. There was neither a difference among the ...
This seems to be due to an optimization figuring that since the weak definitions are all the same and will get linked together, just keeping one across the CGUs is enough. I haven't been able to find the code that does this.Does anyone know where this transformation is implemented?
NAIROBI, Nov. 21 (Xinhua) -- African countries could lose up to 22.4 billion U.S. dollars over the next decades if they fail to improve their surveillance system for vaccine-preventable diseases (VPD), the World Health Organization (WHO) warned on Thursday. ...
The elderly women suffering breast cancer who lived in nursing homes and experienced functional impairment in their daily activities prior to treatment had the highest rates of one-year mortality. Around 61 seniors living in the nursing homes received the most invasive treatment, such as axillary lym...
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