.CH "Getting Started"
.MH "Prerequisites"
We assume that you are already familiar with
the Subsystem; that you can create, delete, edit and list files;
redirect input and output; obtain on-line documentation, etc.
We also assume that you are familiar with the C programming
language.
If you are not, you should examine
the [ul Software Tools Subsystem User's Guide] and
[ul The C Programming Language] by Kernighan and Ritchie
before continuing in this guide.
.pp
Throughout this guide, we
boldface user input in our examples, as is the convention
in the [ul Software Tools Subsystem User's Guide].
.#
.MH "Calling the C Compiler"
There are several commands that call the C compiler:
.be 3
cc      - compile a C program
ccl     - compile and load a C program
ucc     - "Unix-like" C compile and load
compile - general purpose compiler interlude
.ee
We follow with a brief description of each.
For detailed information
and examples
refer to the Reference Manual entries for each command,
e.g.:
.be 1
] [bf help cc]
.ee
.#
.SH "Cc --- compile a C program"
'Cc' behaves much like the other Subsystem compiler interfaces.
It is a program that takes a file whose name ends in ".c" and
calls the programs necessary to convert it into a relocatable
object program in a file whose name ends in ".b".
'Cc' calls two major programs:  the compiler front end 'c1',
and the code generator 'vcg'.
If you have no compile-time errors in your program, you will
not see [ul any] messages at all from either program.
'Cc' automatically "includes" the file "=cdefs="
(which is "=incl=/swt_def.c.i") containing
macros and external data declarations for the C Standard I/O Library
and for interfacing with the Subsystem.
.#
.SH "Ccl --- compile and load a C program"
'Ccl' compiles a ".c" file in the same way as 'cc'; it then
calls 'ld', the Subsystem loader interface, to produce an
executable program in a file with no suffix.
Unfortunately, the Prime loader is somewhat noisy,
so you receive a good bit of output during the execution of 'ld'.
.#
.SH "Ucc --- compile and load a C program"
'Ucc' is a "Unix-style" C compiler and loader.  It is
[bf not], however, exactly like Unix's 'cc' or any other known
Unix program!
'Ucc' recognizes file naming conventions for Subsystem supported
languages and will use the appropriate preprocessor and/or
compiler to process non-C files.  Consequently, it can be
used to compile and load several files of different languages
into an executable program, as long as the main program is written
in C.
'Ucc' now depends on the new 'compile' program to do most of
its work.  It is just smart enough to arrange to call 'compile'
properly; it no longer knows about all the details of the C compiler,
or how to go about compiling other languages.
.#
.SH "Compile --- general purpose compile and load"
'Compile' is a general purpose compiler interlude.
It knows about the Subsystem naming convention for the more
popular languages available under SWT and Primos.
It will arrange to call the proper compiler for each source
file, based on the suffix.  You may tell it to pass options
on to each different compiler or preprocessor, and also to tell
it what is the "main" language, in order for it to load any
necessary libraries and/or start-off routines.
'Ucc' now just rearranges its arguments, and calls 'compile'.
.#
.MH "C Program Development --- An Example"
For this example, the file "inout.c" contains the following C program:
.be 7
main ()         /* copy input to output until EOF */
{
        int c;

        while ((c = getchar()) != EOF)
                putchar (c);
}
.ee
We can compile and load (i.e., link-edit) "inout"
with the command
.be
] [bf ccl inout.c]
.ee
Consistent with Subsystem convention, 'ccl' places the
executable version of "inout.c" in a file named "inout".
You can execute "inout" as follows:
.be 7
] [bf inout]
[bf a]
a
[bf echo me if you dare]
echo me if you dare
[bf <control-c>]
]
.ee