The reordering that GCC may do is unrelated to the reordering an (x86) CPU may do. Let’s start off with compiler reordering. The C language rules are such that GCC is forbidden from reordering volatile loads and store memory accesses with respect to each other, or deleting them, when a sequence point occurs between them … Read more
I found a way to be able to mock bare C functions in google-mock. The solution is to declare foobar to be a weak alias that maps to foobarImpl. In production code you do not implement foobar() and for unit tests you provide an implementation that calls a static mock object. This solution is GCC … Read more
I will echo what others have said: a better algorithm is going to win in terms of performance gains. That said, I work in image processing, which as a problem domain can be stickier. For example, many years ago I had a chunk of code that looked like this: void FlipBuffer(unsigned char *start, unsigned char … Read more
Is there a way to force the old behavior? Yes. You can use this option -Wl,–disable-new-dtags to tell the new linker to use the old behavior, i.e. RPATH. Is it possible to tell the old version of linker to produce the new output (i.e. RUNPATH instead of RPATH)? Yes. Use -Wl,–enable-new-dtags to tell the old … Read more
Take a look at -ftrapv and -fwrapv: -ftrapv This option generates traps for signed overflow on addition, subtraction, multiplication operations. -fwrapv This option instructs the compiler to assume that signed arithmetic overflow of addition, subtraction and multiplication wraps around using twos-complement representation. This flag enables some optimizations and disables other. This option is enabled by … Read more
How much effort are you willing to go to? There’s an obnoxiously obscure way to do it but it requires you to set up a dummy directory to hold surrogates for the system headers. OTOH, it doesn’t require any changes in any of your source code. The same technique works equally well for C code. … Read more
If you don’t declare a function and it only appears after being called, it is automatically assumed to be int, so in your case, you didn’t declare void my_print (char *); void my_print2 (char *); before you call it in main, so the compiler assume there are functions which their prototypes are int my_print2 (char … Read more
Not sure if this addresses your specific problem, but I also had semantic errors. They just came out of the blue after having a working project. Anyway, I fixed it with a single option in workspace settings by setting: “Build configuration for indexer: Use active build configuration” The other option was “Use the build configuration … Read more
Strictly speaking, the question was about checking the lockedness of std::mutex directly. However, if encapsulating it in a new class is allowed, it’s very easy to do so: class mutex : public std::mutex { public: #ifndef NDEBUG void lock() { std::mutex::lock(); m_holder = std::this_thread::get_id(); } #endif // #ifndef NDEBUG #ifndef NDEBUG void unlock() { m_holder … Read more
The page “Notes on Multiple Inheritance in GCC C++ Compiler v4.0.1” is offline now, and http://web.archive.org didn’t archive it. So, I have found a copy of the text at tinydrblog which is archived at the web archive. There is full text of the original Notes, published online as part of “Doctoral Programming Language Seminar: GCC … Read more