| ??? 06/21/06 21:37 Read: times |
#118810 - well... Responding to: ???'s previous message |
Andy Peters said:
Dunno why the function declaration is externed. True, it is not necessary to specify 'extern', but there is nothing wrong nor even particularly unusual about it. It makes some sort of sense to put 'extern' to emphasise that the actual definition (or "implementaion") is external to this compilation unit. It should be declared in a header file that's included by the C source, and not externed. Whether you put the declaration in a header file or the 'C' source file is merely a matter of style; it makes no difference whatsoever to the compiler. In either place, the 'extern' keyword is perfectly permissible - see above. Anyways: your code calls a function lcdinit(). The extern modifier says that "somewhere a function called lcdinit() has a definition." Exactly. However, that definition isn't available. Hence the Linker complains that it is "Undefined"; ie, literally, there is no definition. You need a source file that has the implementation of lcdinit() Not necessarily a Source file - a suitable object file or Library would be fine. and a header file that declares lcdinit()'s interface Again, it is not necessary to use a header file; it is certainly conventional, and often advisable, but not strictly essential. |
| Topic | Author | Date |
| Hi-tech C compile problem | 01/01/70 00:00 | |
| Linker | 01/01/70 00:00 | |
| Less Detail | 01/01/70 00:00 | |
| 'C' Globals | 01/01/70 00:00 | |
| extern-ing a function declaration? | 01/01/70 00:00 | |
| well... | 01/01/70 00:00 | |
| The Secret | 01/01/70 00:00 | |
| case was not an issue | 01/01/70 00:00 | |
| Case still not an issue | 01/01/70 00:00 | |
| Incorrect deduction | 01/01/70 00:00 | |
| Maybe Not | 01/01/70 00:00 | |
| Linker | 01/01/70 00:00 | |
make | 01/01/70 00:00 | |
| use Win98SE in a virtual machine, QEMU? | 01/01/70 00:00 | |
| Vmware | 01/01/70 00:00 | |
| Just a guess | 01/01/70 00:00 | |
| possibly, but | 01/01/70 00:00 | |
| after all the 'logicl' possibilities hav | 01/01/70 00:00 |