[cs631apue] non-homework: welcome.c
jschauma at stevens.edu
Sun Sep 14 14:46:57 EDT 2014
sshah83 <sshah83 at stevens.edu> wrote:
> The second warning is about int being used as char* which implies wrong
> type returned by getlogin() function.
> If I turn on all warnings using below command :
> gcc -Wall welcome.c -o welcome.out
> I see the exact warning leading to the implicit function declaration
> welcome.c:5:2: warning: implicit declaration of function 'getlogin'
> This warning means function prototype for getlogin() is missing and the
> "implicit function declaration" rule in C language means that a default
> declaration that returns int is created implicitly
> The fix would be to include the correct header file which has the right
> function prototype
> #include <unistd.h>
Correct - well done!
Compiling with "-Wall" is always a good idea, but mandatory in this
class. Reading and understanding the messages the compiler gives you
allows you to quickly fix these sorts of things.
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