[Bug c/57531] lvalue required with comma operator

vijunag at gmail dot com gcc-bugzilla@gcc.gnu.org
Wed Jun 5 14:14:00 GMT 2013


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57531

--- Comment #3 from vijay Nag <vijunag at gmail dot com> ---
(In reply to vijay Nag from comment #2)
> Sorry for the confusion. Please try the unit test case below
> 
> #include <stdio.h>
> 
> /*remove assert  in production*/
> 
> #define ASSERT(x) (void)0
> #define GET_VALUE_A(value) ((value)->version == 1 ? ASSERT(value),
> (value)->b : (value)->a)
> 
> struct Lvalue {
>   int version;
>   int a;
>   int b;
> };
> 
> int main()
> {
>   struct Lvalue lvalue = {};
>   lvalue.version = 1;
> 
>   GET_VALUE_A(&lvalue) = 5;
> }
> 
> i686-pc-linux-gnu-gcc -c ternary.c 
> ternary.c: In function ‘main’:
> ternary.c:19:24: error: lvalue required as left operand of assignment
> 
> i686-pc-linux-gnu-gcc -v
> Using built-in specs.
> COLLECT_GCC=~/tools/bintools/linux-x86/gcc/201302221200/bin/i686-pc-linux-
> gnu-gcc-wrapped
> COLLECT_LTO_WRAPPER=~/tools/bintools/linux-x86/gcc/201302221200/libexec/gcc/
> i686-pc-linux-gnu/4.7.2/lto-wrapper
> Target: i686-pc-linux-gnu
> Configured with: ../../gcc/configure --build=amd64-pc-linux-gnu
> --host=amd64-pc-linux-gnu --target=i686-pc-linux-gnu
> --enable-languages=c,c++ --prefix=~tools/bintools/linux-x86/gcc/201302221200
> --enable-shared --with-headers=/tmp/201302221200/new_header/
> --disable-libquadmath --disable-libgomp --disable-libssp
> --disable-libmudflap --disable-libitm --with-fast-fixincludes
> --enable-threads --site=starent --with-gnu-as --with-gnu-ld
> Thread model: posix
> gcc version 4.7.2 (GCC) 
> 
> 
> i586-pc-linux-gnu-gcc -c ternary.c 
> i586-pc-linux-gnu-gcc -v
> Reading specs from
> ~/tools/bintools/linux-x86/gcc/200608191248/lib/gcc-lib/i586-pc-linux-gnu/3.
> 3.6/specs
> Configured with: ../../gcc/configure --build=i686-linux --host=i686-linux
> --target=i586-pc-linux-gnu --enable-languages=c,c++
> --prefix=~/tools/bintools/linux-x86/gcc/200608191248 --enable-shared
> --with-headers=/localdisk/tmp/x86-linux/include --with-fast-fixincludes
> --enable-threads --site=starent --with-gnu-as --with-gnu-ld
> Thread model: posix
> gcc version 3.3.6


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