How to avoid resolving extern symbol?
Softwar Library externs a symbol something like follows:
extern const some_struct_type rtos_config;
My application links this software library. During link time I get the following error:
"error: external symbol not defined: rtos_config"
I don't need to use this symbol in my application. Is there any shortcut way to get around this link error.? How can I define it in my application without populating all the members of the structure?
thanks.
extern const some_struct_type rtos_config;
My application links this software library. During link time I get the following error:
"error: external symbol not defined: rtos_config"
I don't need to use this symbol in my application. Is there any shortcut way to get around this link error.? How can I define it in my application without populating all the members of the structure?
thanks.
Infinity08
It seems you didn't link your code to the library. If you don't link to it, you won't be able to use any of its features. If you link to it, all features of the library are available. There's no real middle way ...
ASKER
If library has a reference as follows:
extern const unsigned int some_var;
If I don't define this variable in my application, I'll get a linker error. I don't need this variable but I'll define it anyways so the linker error goes away. But if this variable was type some large strucuture then, I would have to set all the members of the structure. Is there anyway to define a variable as unused or something so I don't have to populate all the members of the structure.
extern const unsigned int some_var;
If I don't define this variable in my application, I'll get a linker error. I don't need this variable but I'll define it anyways so the linker error goes away. But if this variable was type some large strucuture then, I would have to set all the members of the structure. Is there anyway to define a variable as unused or something so I don't have to populate all the members of the structure.
If the header file of the library contains this line :
extern const some_struct_type rtos_config;
then it means that the library defines that variable. You don't have to define it yourself in your application - you simply have to link your code against the library.
extern const some_struct_type rtos_config;
then it means that the library defines that variable. You don't have to define it yourself in your application - you simply have to link your code against the library.
ASKER
I believe the library is only referencing rtos_config variable. Applications are expected to define it. All our applications that use operating system define this variable. My application doesn't have operating system so I don't need to define this variable but I have to in order to avoid the link error. Can I define it unused so I don't have to populate all the members of the structure.
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