https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61817
Bug ID: 61817
Summary: Inconsistent location of tokens in the expansion list
of a built-in macro
Product: gcc
Version: 4.10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: preprocessor
Assignee: unassigned at gcc dot gnu.org
Reporter: dodji at gcc dot gnu.org
Consider this function-like macro definition in the inc.h file
------------------->inc.h<-------------------
#define F() const int line = __LINE__
------------------->8<-----------------------
Now consider its use in a file test.c:
------------------>cat -n test.c<----------------
1 #include "inc.h"
2
3 void
4 foo()
5 {
6 F
7 (
8 )
9 ;
10 }
------------------->8<---------------------
Running test.c through cc1 -quiet -E yields:
--------------------->8<--------------------
# 1 "test.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "/usr/include/stdc-predef.h" 1 3 4
# 1 "<command-line>" 2
# 1 "test.c"
# 1 "inc.h" 1
# 2 "test.c" 2
void
foo()
{
const int line =
8
;
}
--------------------->8<----------------------
Note how tokens "const", "int", "line" and "=" are all on the same line as the
expansion point of the function-like F() macro, but how the token "8",
resulting from the expansion of the built-in macro __FILE__ is on the same line
as the closing parenthesis of the invocation of F().
This is the problem. The result of the __FILE__ macro should be "6" and should
be on the same line (line 6) as the other tokens of the expansion-list of F().
This issue actually holds for the expansion of all built-in macros.
So more generelly, I would describe the issue as such:
When expanded in a function-like macro, the location of resulting tokens of a
built-in macro is set to the closing parenthesis of the enclosing function-like
macro invocation, rather than being set to the location of the expansion point
of the invocation the enclosing functin-like macro.
