Integer promotion and overflow

[Keith Thompson]

is my interpretation correct though?

for example,

long long foo = 5000000000;

if 5000000000 cannot be represented by the type int
then the compiler sees if it can be represented by type long int
and if not, then it tries long long int.

I tried this with gcc invoking -std=c99 and it seems to initialize
to the correct value but issues a warning. Should it issue
the warning? If my interpretation is correct then I do not see how this
warrants a diagnostic.

I wouldn't expect a warning in that case, but as infobahn points out
the standard allows a compiler to issue any diagnostic it likes.

You don't tell us what the warning is, so it's impossible to tell
what's going on. I tried compiling the above with several versions of
gcc. More recent versions give a warning

tmp.c:1: warning: integer constant is too large for "long" type

without "-std=c99"; none that I tried give a warning with "-std=c99".