#if defined(CONDITION_A) && defined(CONDITION_B)
时间: 2024-03-21 18:43:34 浏览: 29
#if defined(CONDITION_A) && defined(CONDITION_B)是一个C语言预处理器指令,可以用来检查CONDITION_A和CONDITION_B是否都被定义。如果这两个条件都被定义,则执行#if和#elif之间的代码,否则执行#else和#endif之间的代码。
下面是一个示例:
```
#if defined(CONDITION_A) && defined(CONDITION_B)
// 如果CONDITION_A和CONDITION_B都被定义,则执行此处的代码
#else
// 如果CONDITION_A和CONDITION_B中至少一个未被定义,则执行此处的代码
#endif
```
请注意,#if和#elif之后的条件表达式必须在编译时求值,因此必须是常量表达式。因此,CONDITION_A和CONDITION_B必须是预定义的宏。
相关问题
NameError: name 'calc_condition_number' is not defined
这个错误是因为调用`calc_condition_number`函数时,Python无法找到该函数的定义。你需要先定义该函数,然后才能调用它。
你可以将上面的代码完整地复制到Python文件中,或者在交互式环境中依次执行代码块,确保所有依赖的函数都已经定义。然后再调用`calc_condition_number`函数,就不会出现这个错误了。
60 | #if PTHREAD_STACK_MIN > 0 | ^~~~~~~~~~~~~~~~~
The line you provided appears to be part of a conditional compilation directive using the `#if` preprocessor directive. It checks if the value of `PTHREAD_STACK_MIN` is greater than 0.
In this case, `PTHREAD_STACK_MIN` is a constant defined in the `pthread.h` header file, which represents the minimum size (in bytes) of a thread stack.
The code within the `#if` directive will be compiled if the condition is true, that is, if `PTHREAD_STACK_MIN` is indeed greater than 0.
If you encounter an error related to this line, it's possible that there's an issue with the definition of `PTHREAD_STACK_MIN` or with the inclusion of the `pthread.h` header file. Make sure that you have included the necessary header files correctly and that any required libraries are linked properly during the compilation process.
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