Executable C source

test.c

#define C_AND_POSIX_SHELL_POLYGLOT /*
# This section gets interpreted by the POSIX shell.
# It is inside a C comment, so it gets ignored by the C compiler.

CFLAGS=
NIXPKGS=
TARGET=/tmp/a.out

exec nix-shell \
    --pure \
    --packages clang_12 ${NIXPKGS} \
    --command "echo Compiling && clang++ ${CFLAGS} ${0} -o ${TARGET} && echo Running && ${TARGET} ${@}"

# The exec ensures shell does not interpret beyond this point.
*/

#include <iostream>

int main() {
	std::cout << "Hello, world!" << std::endl;
}

/*
This is a self-contained C source file: If you run this at the shell,
and it will find its own dependencies (through Nix), compile itself,
and run itself.

Usage:

    $ sudo apt install -y nix
    $ chmod +x test.cpp
    $ ./test.cpp
    Compiling
    Running
    Hello, world!

See: https://gist.github.com/charmoniumQ/729ea258e1bcdc13476c89a6683c9206

*/