Hello all,

I have a doubt. It's about Jesus Alvarez's my_strncpy function.
Is it correct not to close the array? Though I see, it is initialized by '\0 '.
Is this the normal behavior on declaring a character array?

Greetings,
Jose G. López

Hi Jose,

Welcome to the wiki!

As you can probably tell, this wiki is very inactive, so you might not get many responses to your questions. I haven't coded C in quite a while, so I'm not confident in my reply, but I'll give it a go anyway, given that other responses might not be so forthcoming.

Firstly, the failure to terminate the destination string in Jesus Alvarez's my_strncpy function appears to me to be a bug.

Secondly, I once wrote this note to myself about variable initialisation, although I can't recall my sources, so you might want to research to confirm that it's correct: "Static and global variables are set to their representation of zero or NULL; automatic variables (i.e. as part of a non-file-scope block, such as within a function) are not initialised." In other words, if my note is correct, then the buf_1 array is in fact not initialised at all, and any seeming initialisation to '\0' is a happy accident. You might want to post to comp.lang.c for more expert opinions though: as I mentioned, I'm not really up on the finer points of C at the moment.

--Laird (Netocrat) 06:52, 16 April 2010 (UTC)

Thank you very much Laird,

You were very helpful. I found this quote in K&R2, page 39:

External and static variables are initialized to zero by default. Automatic variables

for which is no explicit initializer have undefined (i.e.,garbage) values.

--Jose G. López (Josgalo)