Keith-S-Thompson

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Keith-S-Thompson

/*
 * In response to http://stackoverflow.com/a/22918463/827263 
 * "In C you can't declare variables/functions (in same scope) with the same name more than once."
 */

#include <stdio.h>

void yes_you_can(void);
void yes_you_can(void);
void yes_you_can(void);

Keith-S-Thompson

#include <stdio.h>
#include <stdint.h>
int main(void) {

    int64_t u = 0;
    int i;

    for(i=0;i<44;i++)
        u |= (uint64_t)1 << i;

Keith-S-Thompson

Demo for clang bug (demonstrated with version 3.4)
Based on this question on Stack Overflow.

===

It turns out that this isn't a bug; see Jens Gustedt's answer to the question.

Keith-S-Thompson

This small C++ program demonstrates an apparent optimization bug in g++.

It's based on a question on Stack Overflow: Does C++ allow an optimizing compiler to ignore side effects on the for-condition?. (I'm reasonably sure the answer in this case is no.)

Keith-S-Thompson

I believe I've found a bug in the implementation of the "==" operator for pointers in both gcc and clang.

pointer_equality_bug.c is a demonstration of the bug.

Quoting N1570 6.5.9p6:

Two pointers compare equal if and only if both are null pointers,

Keith-S-Thompson

This is a simplified test case for this question on Stack Overflow.

Keith-S-Thompson

This is a CVS demo script for this question posted by Paul Bunch on Stack Overflow.

The cvs annotate command prints a message on standard error of the form:

Annotations for hello.txt
***************

The questioner is trying to redirect that message when invoking cvs annotate from a Perl script. I have so far been unable to reproduce the problem. I ask Paul Bunch to try running this script on his own system.

Keith-S-Thompson

This is foo.txt.

I'm just trying out this "gist" thing.

Hey, and I can edit it!

Keith-S-Thompson

/*
 * Reference: http://stackoverflow.com/questions/9169453/gcc-4-4-3-offsetof-constant-expression-bug-how-should-i-work-around-this
 * Should compile and execute without error or warning with:
 * gcc c.c -pedantic -std=c89 -o c && ./c
 * or
 * gcc c.c -pedantic -std=c99 -o c && ./c
 */

#include <stddef.h>
#include <stdlib.h>