错误:表达式必须具有恒定值 [英] error: expression must have a constant value
问题描述
我需要一些帮助来查找如何解决此错误.
I need some help to find how to resolve this error.
typedef struct {
const char *iName;
const char *iComment;
} T_Entry;
const T_Entry Menu_PowerSupply = { "PWRS", "Power supply"};
static const T_Entry G_Commands[] = {
{ "MEM", "Memory"},
{Menu_PowerSupply.iName,Menu_PowerSupply.iComment},
{ "SYS", "System"}
};
我收到错误消息:表达式必须具有恒定值 我该如何解决?
I got the error : expression must have a constant value How can I solve this ?
对我来说,链接时间是已知的,并且在固定地址处具有固定值:我错了吗
For me at link time is known and at a fixed address with a fixed value : Am I wrong
我的目的是将以下代码放入库中
My purpose is to put the following code into a library
const T_Entry Menu_PowerSupply = { "PWRS", "Power supply"};
以下内容也不起作用
static const T_Entry G_Commands[] = {
{ "MEM", "Memory"},
Menu_PowerSupply,
{ "SYS", "System"}
};
如果有人可以帮助我理解此 非const 值...
If someone could help me to understand this non const values ...
推荐答案
该错误是因为全局变量的初始化程序必须是常量表达式,但是即使Menu_PowerSupply
被定义为const
,它也不是常量表达式.
The error is because the initializer for global variables must be constant expression, but even though Menu_PowerSupply
is defined as const
, it's not a constant expression.
这类似于:
const int n = 42;
int arr[n];
不能在C89中编译,因为n
不是常量表达式. (它仅在C99中才编译,因为C99支持VLA)
doesn't compile in C89 because n
is not a constant expression. (it does compile in C99 only because C99 supports VLA)
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