#if 0?0?0:0:0

[Francois Grieu]

The following 4-lines source fragment test.c (fourth line empty)
#if 0?0?0:0:0
#endif
int main(void){return 0?0?0:0:0;}

cause:
test.c(1) : fatal error C1017: invalid integer constant expression
when compiled by cl.exe aka "Microsoft (R) 32-bit C/C++ Optimizing
Compiler Version 15.00.30729.01 for 80x86".

On the other hand this compile and runs fine.
#if 0?(0?0:0):0
#endif
int main(void){return 0?0?0:0:0;}

Did I hit a but it this compiler's preprocessor?

Francois Grieu

[Eric Sosman]

Looks like ig.

--
Eric Sosman
eso...@ieee-dot-org.invalid

[Sjouke Burry]

No it is a case of a TA.

[Francois Grieu]

I wrote:
> The following 4-lines source fragment test.c (fourth line empty)
> #if 0?0?0:0:0
> #endif
> int main(void){return 0?0?0:0:0;}
>
> cause:
> test.c(1) : fatal error C1017: invalid integer constant expression
> when compiled by cl.exe aka "Microsoft (R) 32-bit C/C++ Optimizing
> Compiler Version 15.00.30729.01 for 80x86".
>
> On the other hand this compile and runs fine.
> #if 0?(0?0:0):0
> #endif
> int main(void){return 0?0?0:0:0;}
>
>

> Did I hit a bug in this compiler's preprocessor?

The consensus is yes. I duly reported it. And the (representative of)
the compiler vendor says: "We were able to reproduce this issue. But
Unfortunately we will not fix this issue as it is not a common code and
is not a high priority issue. Thanks for playing with our product."

https://connect.microsoft.com/VisualStudio/feedback/details/546053/if-1-1-1-1-1-cause-error-fatal-error-c1017-with-c-compiler-16-00-30128-01

I should probably have reported the problem as:

// return the smallest of x y z
#define MIN3(x,y,z) ( (x)>(y) ? (y)>(z) ? (z) : (y) : (x) )

#define ALPHA 5
#define BETA 4
#define GAMMA 6

#if MIN3(ALPHA,BETA,GAMMA) < 2
#error "check ALPHA BETA GAMMA"
#endif

int main(void){return 0?0?0:0:0;}

Francois Grieu