Why C compiler wouldn't accept this conditional assignment?

Question

I was wondering why binary numbers can't be used with bitwise operators?

//works
msgSize = (*(msgbody+1) & 0x80)?*(msgbody+5):*(msgbody+3); 

//doesn't compile
msgSize = (*(msgbody+1) & 0b10000000)?*(msgbody+5):*(msgbody+3);

I presume you're programming with gcc... C doesn't have binary literals. — autistic, Mar 29 '13 at 03:01
@modifiablelvalue you were first :) I'm working with IAR (not sure what compiler it uses). Binary literals work fine with Clang setup for ObjC. — bioffe, Mar 29 '13 at 03:04
Irrelevant. An SSCCE might look like [this](http://ideone.com/T050u3). As you can see from my SSCCE, there are no binary literals in C. — autistic, Mar 29 '13 at 03:09
Put it as an answer. I'll mark it answered. My error code looks different. My guess IAR is not GCC based. — bioffe, Mar 29 '13 at 03:11
possible duplicate of [Can I use a binary literal in C or C++?](http://stackoverflow.com/questions/2611764/can-i-use-a-binary-literal-in-c-or-c) — Alok Save, Mar 29 '13 at 03:15
You said "guess". I wanted to clarify and remove the guessing. — JesperE, Apr 03 '13 at 10:35

score 1 · Accepted Answer · answered Mar 29 '13 at 03:16

Binary literals aren't supported in C; If they're available, they're an extension. I would suggest that your compiler is emitting an error because it doesn't recognise the binary literal 0b10000000. Hence, your compiler probably emits an error on this, too:

int main(void) {
    int msgSize = 0b10000000;
    return 0;
}

I would suggest using 0x80 or 1 << 7 instead.

Why C compiler wouldn't accept this conditional assignment?

1 Answers1