2007/6/15, Devvrat Tripathi <tripathidevvrat@xxxxxxxxx>:
can we declare an extern function(or say variable) inside the kernel and then later define it using a kernel module.
I don't think this is possible (at least it isn't in OpenSolaris). The reason is that extern has as a purpose to tell the compiler that it should not worry that it can not find the function or variable. You assure him that it is there somewhere in some file. However, when linking all object files together, all functions should be present, otherwise you get a linker error. If you put the function or variable in a module, this means it is not compiled together with the kernel and thus the linker will not know what to do with it. In OpenSolaris this issue can be resolved by using a function which searches for the location of a certain symbol (variable or function) at runtime and can then execute it. In OpenSolaris this function is called kobj_getsymvalue(), but I'm pretty sure that Linux will provide a similar mechanism.. Thomas -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
