RE: What to do with a.out

["Rupert Wood" <me at rupey dot net>]

DSC Siltec wrote:

> I wrote one okay; ran gcc hello.c ; and got a.out
> 
> Question 1:  What do I do with a.out ?
:
> or run it by typing its name.

Execute it: try './a.out'. It's the default name for a linked
executable. If you want to specify another name, use the '-o' switch.

Unlike dos/windows/etc., most unix-alikes won't check the current
directory for an executable unless you explicitly add it to your PATH.
You can use './<name>' to execute a file in the current directory.

You can use 'file <whatever>' to identify file types; it'll say
something along the lines of:

    fox:~$ file a.out
    a.out:          ELF 32-bit MSB executable SPARC Version 1

except probably 'LSB i686' or some veriane

>   2:  Where exactly do I find documentation on the library routines,
> both the standard GCC ones, and then also the X11R6 routines?

  man <function-name>

The standard library functions, though, *aren't* GCC's. They belong to
the operating system's C library - in the case of GNU/Linux, this would
be glibc. GCC does, however, provide a number of language extensions and
built-ins; for those, see the GCC manual.

> I'd like to be able to write simple programs with graphics, and have
> decided that I'd prefer X to SVGALIB.

If you want to program for X, you may find it easier to use a toolkit
such as gtk (C) or KDE (C++). Try www.gnome.org.

>   3.  In order to avoid asking such questions as this in the 
> future, is there a newbie GCC FAQ somewhere?

Not that I know of. But other usual questions are:

 * Using maths functions cause linker errors - you need to link in
   the maths library with '-lm'

 * Using 'gcc' to link C++ code causes linker errors for ostream,
   etc. - you should link C++ code using the g++ driver

 * C++ STL types don't exist in the global namespace; you need to
   import them from the std namespace or address them 'std::'.

Good luck,
Rup.