Initialized and declared ‘extern’的warning

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August undefined, 2024

Webb结果报 'print' initialized and declared 'extern' 警告，后来把引用和赋值分开写，Warning disappear extern int print; /*引用外部/全局变量*/ print = 2; 记：我是个追求完美的人， … Webb2 feb. 2024 · 在以下程序中，我认为extern int i;会更改以下i，以参考i在main外部定义的i:. #include extern int i=1; // warning: 'i' initialized and declared 'extern' int main() { int i=2; printf("%d\n", i); extern int i; // error: extern declaration of 'i' follows declaration with no linkage printf("%d\n", i); return 0; }

关于extern以及源文件和头文件的应用_declared extern_qq_35185913的 …

Webb9 dec. 2014 · 印象中以前學過C語言中跨檔案的全域變數是這樣宣告的。檔案一：int g_var1; 檔案二：extern int g_val1; 然而，我從來沒有想過如果沒有extern的情況會發生什麼狀況。加上之前看過的objdump和nm後手癢，所以把可能的排列組合看看可能發生什麼事。 Webb29 apr. 2024 · Bug. torchvision failed to build with latest pytorch master. Same build script was working weeks ago, indicating this can be a recent regression. good chopper

extern declaration - C / C++

WebbInvestigate and fix any code that has extern variables that are initialized, by removing the initialization or by removing the extern storage class specifier. Problem: I received the following warning: type 'CMOA()::itcpc' with no linkage used to declare variable 'CMOA()::itcpc* itcpc_ptr' with linkage [enabled by default] Webb27 juni 2014 · The extern keyword means "declare without defining". In other words, it is a way to explicitly declare a variable, or to force a declaration without a definition. It is … Webb26 aug. 2024 · extern最基本的用法是声明全局变量的。这里需要注意两点，一是“声明”，二是“全局变量”；我们先来分析这两个概念。声明：声明和定义是有区别的。声明不等于定义，声明只是指出了变量的名字，并没有为其分配存储空间；定义指出变量名字同时为变量分配存储空间，定义包含了声明。例如： extern int i; //声明变量i，但没分配存储 … healthmedocs

Initialization of external variables - IBM

Webb6 jan. 2024 · You need to declare them as 'extern' in the .h file if you include variables.h in several .cpp files. But then you have to define them in another place - usually in one of … WebbYou can't (the compiler is letting you as an extension, but with a warning) initialize a variable at the declaration, only at the definition (there should be a int sizeArrayin some .c file). Remove this initialization and do it at the definition instead. healthmed pharmacy calgaryWebb4 feb. 2014 · warning: 'extern' variable has an initializer [-Wextern-initializer] This warning is not important, as defining the variable with int counter = 0; still yields a static duration … healthmed pharmacy edmonton

"Webb3 apr. 2008 · An external variables can only be carried out once initialized, and must be carried out in the definition of variables Extern char permis = 'Y'; / * wrong * / Please … " - Initialized and declared ‘extern’的warning

Initialized and declared ‘extern’的warning

Webb16 sep. 2024 · I get the following warning: warning: 'X' is initialized and declared 'extern' and it looks like it's no big deal and I could disable it. Changing the code is not really a good idea in my case because I have no control over the code, I just need to compile it. So I want to disable the warning. Webb9 maj 2011 · Created attachment 22024 file "external.c", a short test case exhibiting the problem Given the attached source file, GCC (powerpc-eabi-gcc.exe (Sourcery G++ Lite 4.4-79) 4.4.1), invoked as: powerpc-eabi-gcc -te500v1 -mcall-sysv-noeabi -MMD -Wno-parentheses -c -o ex ternal.o external.c reports: external.c:3: warning: 'i' initialized …

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Webb9 maj 2011 · -Wall -Wextra emits no warning for static int i; extern int i; case. In fact, there is -Wredundant-decls, but it only works if there is no initialization in the extern … Webb15 nov. 2005 · An extern decleration means that a variable is declared and no memory is allocated for it. I've always tought extern means: the variable is declared 'somewhere else' but I want to use it in this file. Not: declared but no memory is allocated. If you try to extern an 'unallocated' variable the compiler

Webb20 feb. 2024 · 1から自分で作ると全部main.cに書いてしまうので気にもしていなかったが、複数のファイルにまたがる場合のグローバル変数の宣言にはexternをつけるのだそうだ。. 斜めに検索した限りでは、. hoge.h. とかのヘッダファイルを用意して、これに. extern usigned char ...

Webb31 dec. 2024 · It is at best aconventional to use extern type name = value; — use either extern type name; or type name = value; but not both. You should either declare (but … Webb10 aug. 2011 · 追答. 定义只能有一次. 带extern的不算定义，extern的作用是声明这个变量在别的文件中已经被定义，让编译器去别的文件中找. 如果你两个都有extern，编译器是找不到真正的定义的. 本回答由提问者推荐. 2. 评论. 分享. 举报.

Webb12 juni 2009 · extern声明的全局变量的作用范围是整个工程，我们通常在“.h”文件中声明extern变量之后，在其他的“.c”或者“.cpp”中都可以使用。extern扩大了全局变量的作用 …

Webb8 dec. 2004 · extern "Language Name" 则表示是某种语言的变量声明。所以，这并不是编译器的bug，编译器给出的警告是正确的，因为你在该处对变量进行了初始化，这会强制编译器分配内存并初始化，而这可能会导致错误（因为你可能在别处定义了这个变量）。而加上大括号以后，只是对编译器的一种欺骗，但是真正错的仍然是你，而非编译器：） … health meds4uWebbThe initializer for an extern object must either: Appear as part of the definition and the initial value must be described by a constant expression; or; Reduce to the address of a previously declared object with static storage duration. You may modify this object with pointer arithmetic. good chop websiteWebb9 aug. 2024 · warning: 'b' initialized and declared 'extern' 1 声明或定义中如果没有类型则采用默认类型，并产生警告。当然这取决于你的编译选项设置。 a = 1; //定义 1 编译结果： warning: data definition has no type or storage class a = 1; ^ warning: type defaults to 'int' in declaration of 'a' [-Wimplicit-int] 1 2 3 4 1.2 对于函数通过是否带有函数体区分定 … health med plusWebb17 dec. 2024 · 在a.c中进行全局变量的定义：1）exetrn int a = 5; 会跳出警告 ( a.c:3:12: warning: 'a' initialized and declared 'extern' [enabled by default] ),意思是你在头文件中进行了extern的声明，定义的时候已经默认使用extern的初始化和声明，即使用2）种方法进行定义 2）int a = 5; 在b.c文件中使用的时候（extern int a;）可以不写，程序会在别的 … healthmed provider portalWebb另外，extern关键字只需要指明类型和变量名就行了，不能再重新赋值，初始化需要在原文件所在处进行，如果不进行初始化的话，全局变量会被编译器自动初始化为0。像这种写法是不行的。 extern int num=4; 但是在声明之后就可以使用变量名进行修改了，像这样： #include int main () { extern int num; num=1; printf ("%d",num); return 0; } 如 … good cholesterol readings womenWebb最佳答案一旦在 i 函数中定义了一个名为 main 的变量，文件范围内的 i 将被屏蔽并且无法访问 (除非您具有其地址)。当您以后添加声明 extern int i 时，这与在相同作用域内的名为 i 的局部变量冲突，因为本地人无法进行外部链接。它确实是而不是，但可以访问全局 i 。当您删除本地 i 时， extern int i 声明与文件范围内的定义匹配，因此没有错误。至于 … good chop redditWebbfile.c:1:12: warning: 'var' initialized and declared 'extern' 因为 extern 的存在通常意味着程序员打算写一个变量声明 (否则你为什么要使用 extern ？ )，但初始化器却把它变成 … good chop reviews and ratings and complaints