从Windows在Unix上开发C ++，本机函数调用？

Question

I'd like to ask a few specific questions regarding writing C++ on Unix as opposed to windows.

1. In windows, to call native OS functions you usually link to a .dll or include windows.h Likewise, how do you refer to the underlying OS functions in Unix?

2. Is there a reference guide for all the underlying OS functions within Unix? (so that one could see what functions are available).

3. What is the best method to "include" the boost libraries? To use an IDE like the eclipse C/C++ version and include boost like one would on windows?

Thank you

Answer 1

1) There is no single header file. You do not call system calls directly, instead they are generally invoked indirectly through the standard c library like fopen (in the case of fopen, you can also call the underlying function open, but that makes a program less portable). Mentioning which system calls specifically you refer to would help

2) It sounds like you are a new to development on the Unix platform. I highly recommend "Advanced Programming in the UNIX Environment" by Richard Stevens.

3) You should get familiar with the make utility. Something that is generally hidden on windows by your IDE. In addition the boost library comes with example programs.

Answer 2

1. There is no single header that you can include to have access to all *nix functions; see the corresponding man page in sections 2, 3, or 3p for the relevant function in order to tell which headers and libraries you need.

2. Each *nix tends to follow POSIX or SUS to varying degrees.

3. ... What?

Answer 3

On Unix systems the Unix functions are typically in libc along with the C standard library. The compiler automatically links this to your executable, typically as a 'shared library', which is sort of like a Windows DLL, but also not exactly.

As for the headers to include... most Unix systems come with the command line man command which allows you to pull up manual pages about various calls. These manual pages generally mention the header you need in order to use a particular function.

There are special functions that are implemented as system calls. For the average C programmer, the fact that a particular function is a system call is an implementation detail. But it's often worth noting exactly which functions these are as they help you understand what the OS does for you, and what's being done by a library you're using. This distinction tends to be very difficult to ascertain on Windows.

Most Unix programmers still use make and command line utilities. That means there's no IDE settings or anything. You're going to have to figure out what flags to pass the compiler. This is generally not all that difficult.

Also, most Unix systems do not install software willy-nilly all over the filesystem. If it's an include file that's part of an installed package, it will be in the /usr/include directory. This means you will not have to magically divine the locations of the Boost include files. They will be in /usr/include along with everything else.

And while you might have to figure out exactly which Boost libraries you need (like -lboost_filesystem ), all the Boost libraries will be in /usr/lib , or /usr/lib64 with all the other libraries, so you won't have to figure out where they are.