gcc4

问题 I'm compiling some c++ code in MinGW GCC 4.4.0, and getting warnings with the following form... warning: invalid access to non-static data member '<membername>' of NULL object warning: (perhaps the 'offsetof' macro was used incorrectly) This problem seems familiar - something I've tried to resolve before and failed, I think, but a while ago. The code builds fine in Visual C++, but I haven't built this particular code recently in any other compiler. The problem code is the following template..

问题 I'm trying to install Imagemagick on OSX Lion but something is not working as expected. -> brew install imagemagick /usr/local/git/bin/git ==> Cloning https://github.com/adamv/ImageMagick.git Cloning into /Users/klebershimabuku/Library/Caches/Homebrew/imagemagick--git... fatal: https://github.com/adamv/ImageMagick.git/info/refs not found: did you run git update-server-info on the server? Error: Failure while executing: git clone --depth 1 https://github.com/adamv/ImageMagick.git /Users/kleber

问题 Premise I’m using a C library (from C++) which provides the following interface: void register_callback(void* f, void* data); void invoke_callback(); Problem Now, I need to register a function template as a callback and this is causing me problems. Consider the following code: template <typename T> void my_callback(void* data) { … } int main() { int ft = 42; register_callback(reinterpret_cast<void*>(&my_callback<int>), &ft); invoke_callback(); } This gives me the following linker error (using

问题 Update - Many people are insisting I need to declare an iVar for the property. Some are saying not so, as I am using Modern Runtime (64 bit). I can confirm that I have been successfully using @property without iVars for months now. Therefore, I think the 'correct' answer is an explanation as to why on 64bit I suddenly have to explicitly declare the iVar when (and only when) i'm going to access it from a child class. The only one I've seen so far is a possible GCC bug (thanks Yuji). Not so

问题 In chapter 3 of Programming: Principles and Practice using C++ (sixth printing), Stroustrup states (p.68): "Note that sqrt() is not defined for an int " . Here is a simple C++ program based on that chapter: #include "std_lib_facilities.h" int main() { int n = 3; cout << "Square root of n == " << sqrt(n) << "\n"; } Given the quote above, I would expect the process of compiling or running this program to fail in some way. To my surprise, compiling it (with g++ (GCC) 4.2.1) and running it

问题 I could build openssl in xcode 3.5.2, but recently I upgraded to Xcode 4.2.1. Now when I try to build in the same old Xcode, I'm getting errors. Make[1]: /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2: No such file or directory Cp: libcrypto.a: No such file or directory Cp: libssl.a: No such file or directory Can I have a solution for this? 回答1: I found the solution for XCode 4. You need to change in "Build Phases" the text $PLATFORM_DEVELOPER_BIN_DIR/gcc-4.2 to $PLATFORM

问题 I am using gcc 4.4.3 on ubuntu. I installed cmph library tools 0.9-1 using command sudo apt-get install libcmph-tools Now, when I tried to compile example program vector_adapter_ex1.c , gcc is able to detect cmph.h library in its include file but is showing multiple errors like vector_adapter_ex1.c:(.text+0x93): undefined reference to cmph_io_vector_adapter' vector_adapter_ex1.c:(.text+0xa3): undefined reference to cmph_config_new' vector_adapter_ex1.c:(.text+0xbb): undefined reference to

问题 I am developing a library and need to make sure it compiles with 4.1.2(I know, it brings me no pleasure). So on a Fedora 14 Machine I downloaded, compiled and installed GCC41. Now in CMake I only change the following to variables CMAKE_CXX_COMPILER=/opt/gcc41/bin/c++41 CMAKE_C_COMPILER=/opt/gcc41/bin/gcc41 It compiles fine, but it seems to use the wrong version of the standard library. The error(s) I get look like this: /opt/gcc41/bin/c++41 -Wall -Wold-style-cast -Wsign-compare -Wnon-virtual

问题 I'm having trouble with compiling a piece of code I have been given for my research. It consists of one component written in C++ and the other in FORTRAN. I think the problem is to do with my gcc version. The first file for example is a C++ file (foo.ccp) #include <iostream> using namespace std; extern "C" { extern int MAIN__(); } int main(){ cout << "main in C++\n"; return MAIN__(); } The second is bar.f90: program test implicit none print*, 'MAIN in FORTRAN' end program test I'm trying to

问题 No, this is not a duplicate of How to detect integer overflow?. The issue is the same but the question is different. The gcc compiler can optimize away an overflow check (with -O2), for example: int a, b; b = abs(a); // will overflow if a = 0x80000000 if (b < 0) printf("overflow"); // optimized away The gcc people argue that this is not a bug. Overflow is undefined behavior, according to the C standard, which allows the compiler to do anything . Apparently, anything includes assuming that