http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48383
Summary: Line continuations handled incorrectly in 4.5 and
above
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: preprocessor
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: d...@cowlark.com
Given the following test file:
foo \
bar
...then if I preprocess it with gcc 4.4 (using gcc -E), I get this:
foo bar
...but if I preprocess it with gcc 4.5 or 4.6, I get this:
foo
bar
This would appear to me to violate 5.1.1.2.1.2 of the C99 draft, which states:
> Each instance of a backslash character (\) immediately followed by a new-line
> character is deleted, splicing physical source lines to form logical source
> lines.
Given that the following test file:
foo\
bar
...always preprocesses to this:
foobar
...then I suspect that what we've got here is an optimisation to keep line
number information correct on the 'bar' token; the reasoning would presumably
be that since C (and C++) treats newlines like all other whitespace, it makes
no difference whether the 'bar' token is on the same line or a new line.
Unfortunately, I believe the spec doesn't allow this behaviour.
(This is actually biting us because we're using cpp to preprocess files before
passing them to a perl script, and are relying on cpp to glue line
continuations together. As of gcc 4.5, this is no longer happening.)
