I started with a simple raspberry pi cross compile program.  I started adding code and Clang Intellisense is throwing invalid warnings.

I have the function open in the program.  It throws a the following warning:

[Clang Intellisense] Warning: implicit declaration of function ‘open’ is invalid in C99

How is that possible when I have included the following headers:

errno.h
fcntl.h
errno.h
stdio.h
stdlib.h
unistd.h
sys/types.h
sys/stat.h

I also get the following message:

[Clang IntelliSense] include the header <stdlib.h> or explicitly provide a declaration for ‘exit’

No idea why it would say that, when the header is clearly included.  There must be some setting I am missing or does Intellisense not work with cross compile?   When I ask Intellisense to search for a header containing one of the functions it complains about, it can’t find any.  Yet the cross compile builds with out problems.

Any ideas?  Thanks