It’s short for “warn all” — it turns on (almost) all the warnings that g++ can tell you about. Typically a good idea, especially if you’re a beginner, because understanding and fixing those warnings can help you fix lots of different kinds of problems in your code.
gcc can actually compile C++ code just fine. The errors you received are linker errors, not compiler errors. Odds are that if you change the compilation line to be this: gcc info.C -lstdc++ which makes it link to the standard C++ library, then it will work just fine. However, you should just make your life … Read more
Add the path to where your new library is to LD_LIBRARY_PATH (it has slightly different name on Mac …) Your solution should work with using the -L/my/dir -lfoo options, at runtime use LD_LIBRARY_PATH to point to the location of your library. Careful with using LD_LIBRARY_PATH – in short (from link): ..implications..: Security: Remember that the … Read more
Your compiler just tried to compile the file named foo.cc. Upon hitting line number line, the compiler finds: #include “bar” or #include <bar> The compiler then tries to find that file. For this, it uses a set of directories to look into, but within this set, there is no file bar. For an explanation of … Read more
Intel x86 processors use 80-bit extended precision internally, whereas double is normally 64-bit wide. Different optimization levels affect how often floating point values from CPU get saved into memory and thus rounded from 80-bit precision to 64-bit precision. Use the -ffloat-store gcc option to get the same floating point results with different optimization levels. Alternatively, … Read more
Create a .o file: g++ -c header.cpp add this file to a library, creating library if necessary: ar rvs header.a header.o use library: g++ main.cpp header.a
g++ -H … will also print the full path of include files in a format which shows which header includes which
H2CO3 is right, you can use a makefile with the CXXFLAGS set with -std=c++11 A makefile is a simple text file with instructions about how to compile your program. Create a new file named Makefile (with a capital M). To automatically compile your code just type the make command in a terminal. You may have … Read more
The problem is not that you can’t forward-declare a template class. Yes, you do need to know all of the template parameters and their defaults to be able to forward-declare it correctly: namespace std { template<class T, class Allocator = std::allocator<T>> class list; } But to make even such a forward declaration in namespace std … Read more
I went through and found the minimal set of includes that should get the maximum level of warning. I then removed from that list the set of warnings that I feel do not actually indicate something bad is happening, or else have too many false positives to be used in a real build. I commented … Read more