#
A preprocessing directive of the form
# error
pp-tokens
o
p
t
new-line
renders the program ill-formed
.
A preprocessing directive of the form
# warning
pp-tokens
o
p
t
new-line
requires the implementation to produce at least one diagnostic message for the preprocessing translation unit (
[intro.
compliance.
general]
)
.
2
#
Recommended practice
: Any diagnostic message caused by either of these directives should include the specified sequence of preprocessing tokens
.