compiler-flags

问题 How to prevent such code from compiling? #include <vector> #include <limits> #include <iostream> #include <cstdint> int main() { std::vector<int16_t> v; v.emplace_back(std::numeric_limits<uint64_t>::max()); std::cout << v.back() << std::endl; return 0; } g++ and clang with -std=c++14 -Wall -Wextra -Werror -pedantic -Wold-style-cast -Wconversion -Wsign-conversion don't even warn about it. The example also compiles without warnings with std::vector<uint16_t> 回答1: Add -Wsystem-headers to the

问题 To compile my source correctly on Windows, I need to pass the EHs flag to MSVC. This is usually straight forward: cl -EHs -c ... When building for GPU acceleration, I need nvcc to pass this flag along when it invokes cl under the hood. I simply do: nvcc -dc -ccbin cl -Xcompiler -EHs ... yet cl throws a warning: warning C4297: 'someFuncInMyCode': function assumed not to throw an exception but does note: The function is extern "C" and /EHc was specified It seems cl receives the flag EHc ,

问题 To compile my source correctly on Windows, I need to pass the EHs flag to MSVC. This is usually straight forward: cl -EHs -c ... When building for GPU acceleration, I need nvcc to pass this flag along when it invokes cl under the hood. I simply do: nvcc -dc -ccbin cl -Xcompiler -EHs ... yet cl throws a warning: warning C4297: 'someFuncInMyCode': function assumed not to throw an exception but does note: The function is extern "C" and /EHc was specified It seems cl receives the flag EHc ,

问题 Is there a way to get gcc to output the available -march=arch options? I'm getting build errors (tried -march=x86_64 ) and I don't know what my options are. The compiler I'm using is a proprietary wrapper around gcc that doesn't seem to like -march=skylake . The flags should be the same so I assume whatever options I'd send to gcc to dump architectures would be the same for this wrapper. I managed to cause gcc to error with a bogus parameter and it dumped a list, but I'm not seeing that now

问题 A java program is giving this warning, with JRE 10.0.2: Java HotSpot(TM) 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release. What is the recommended replacement for this switch? 回答1: Dropping support for CMS and then removing the CMS code, or at least more thoroughly segregating it, will reduce the maintenance burden of the GC code base and accelerate new development. The G1 garbage collector is intended, in the

问题 When I compile this experiment code: int main(void) { int foo = 5; char bar[foo]; } with clang and the '-Weverything' or respectively the separate '-Wvla' flag combined with the '-std=c99' flag, I still get the warning: warning: variable length array used [-Wvla] Example here although C99 conform implementations shall, in comparison to later C standards (C11, C18, etc.) - where the VLA-support is optional, support variable length arrays without exception. Why do I still get this warning for

问题 Unlike Java, in C/C++ following is allowed : int* foo () { if(x) return p; // what if control reaches here } This often causes crashes and hard to debug problems. Why standard doesn't enforce to have final return for non- void functions ? (Compilers generate error for wrong return value) Is there any flag in gcc/msvc to enforce this ? (something like -Wunused-result ) 回答1: It is not allowed (undefined behaviour). However, the standard does not require a diagnostic in this case. The standard

问题 clang, but NOT gcc, has a -Weverything option which appears to include things such as -Wpedantic . You can test it here: https://godbolt.org/z/qcYKd1. See the top-right of the window for where I have typed in -Weverything as an explicit compiler option. Notice the -Wvla-extension warning we get since we are relying on a C99 extension in C++ in this case, and we have -Weverything set. We get the same warning if we just use -Wpedantic , as shown here: https://godbolt.org/z/M9ahE4, indicating

问题 clang, but NOT gcc, has a -Weverything option which appears to include things such as -Wpedantic . You can test it here: https://godbolt.org/z/qcYKd1. See the top-right of the window for where I have typed in -Weverything as an explicit compiler option. Notice the -Wvla-extension warning we get since we are relying on a C99 extension in C++ in this case, and we have -Weverything set. We get the same warning if we just use -Wpedantic , as shown here: https://godbolt.org/z/M9ahE4, indicating

问题 My project uses cuda kernel for a small module and needs nvcc for compiling. During compilation, cmake pass the same linker and compiler flags intended for gcc to nvcc as well. In my particular case, I get the following error. nvcc fatal : Unknown option 'Wl,--no-as-needed' Following the accepted answer in this thread, I managed to remove the compiler flags for the target that needs nvcc as follows. get_target_property(_target_cxx_flags target_that_needs_nvcc COMPILE_OPTIONS) list(REMOVE_ITEM