C++

"C++ is a general-purpose programming language providing a direct and efficient model of hardware combined with facilities for defining lightweight abstractions." - Bjarne Stroustrup, "The C++ Programming Language, Fourth Edition"

Getting Started

This section illustrates the process to compile and run a basic C++ program on the HPC systems.

Hello World

Begin by creating a source file named hello.cpp with the following contents:

#include <iostream>

int main(void) {
  std::cout << "Hello, World!\n";
  return 0;
}

Next, we must select the compiler to use for compiling our program. We can choose among GNU, Intel, and Cray compilers, depending on the system that we are using (see Compilers and Toolchains). To see available modules and versions, use module avail. For this example, we will use the g++ compiler, which is part of GNU's gcc package. We will load the default version of the compiler, which in this case is gcc 10.1:

$ module load gcc
$ module list
Currently Loaded Modules:
  1) gcc/10.1.0
$ gcc --version | head -1
gcc (Spack GCC) 10.1.0

With the gcc package, the C++ compiler is provided by the g++ command. To compile the program, run:

$ g++ hello.cpp -o hello

This creates an executable named hello. Now run the program and observe the output:

$ ./hello
Hello, World!

Compilers and Toolchains

The following is a summary of available compilers and toolchains. User are encouraged to run module avail to check for the most up-to-date information on a particular system.

Toolchain	C++ Compiler	Module	Systems
gcc	g++	gcc	All
Intel	icpc	intel-oneapi-compilers	Swift, Vermilion, Kestrel
Intel	icpc	comp-intel	Eagle
Cray	CC	PrgEnv-cray	Kestrel

Note that Kestrel also provides the PrgEnv-intel and PrgEnv-gnu modules, which combine the Intel or gcc compilers together with Cray MPICH. Please refer to Kestrel Programming Environments Overview for details about the programming environments available on Kestrel.

For information specific to compiling MPI applications, refer to MPI.