https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68118
Bug ID: 68118
Summary: C preprocessor inserts whitespace after macro
parameter substitution
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: preprocessor
Assignee: unassigned at gcc dot gnu.org
Reporter: harry.clauson at hyatt dot com
Target Milestone: ---
The following C macro appears to expand incorrectly:
harry@slack32x:~$ cat test_whitespace.c
#define my_mac(_name,_op,_val) _name _op=_val
my_mac(i,|,4);
my_mac(i,blah,4);
Here is the gcc pre-processor output:
harry@slack32x:~$ gcc -v -E -Wall -Wextra -std=c99 test_whitespace.c
Using built-in specs.
COLLECT_GCC=gcc
Target: i686-pc-linux-gnu
Configured with: ../gcc-5.2.0/configure --prefix=/home/harry/local
--enable-languages=c,c++
Thread model: posix
gcc version 5.2.0 (GCC)
COLLECT_GCC_OPTIONS='-v' '-E' '-Wall' '-Wextra' '-std=c99' '-mtune=generic'
'-march=pentiumpro'
/home/harry/local/libexec/gcc/i686-pc-linux-gnu/5.2.0/cc1 -E -quiet -v
test_whitespace.c -mtune=generic -march=pentiumpro -std=c99 -Wall -Wextra
ignoring nonexistent directory
"/home/harry/local/lib/gcc/i686-pc-linux-gnu/5.2.0/../../../../i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/home/harry/local/lib/gcc/i686-pc-linux-gnu/5.2.0/include
/usr/local/include
/home/harry/local/include
/home/harry/local/lib/gcc/i686-pc-linux-gnu/5.2.0/include-fixed
/usr/include
End of search list.
# 1 "test_whitespace.c"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "/usr/include/stdc-predef.h" 1 3 4
# 1 "<command-line>" 2
# 1 "test_whitespace.c"
i | =4;
i blah=4;
The expansion when _op = | appears to insert whitespace between the parameter
value and the following token (=) which does not appear in the replacement
list.
When _op = blah, the expansion works as expected without inserting whitespace
between the parameter and the following token (=).
Thank you!
