<para>To get one of these packages, all you need to do is to click on

<para>To get one of these packages, all you need to do is to click on

the hotlink for the package, then run

the hotlink for the package, then run

</para>

</para>

<para>as root. Obviously, you will need to have a fully functional FreeBSD

<para>as root. Obviously, you will need to have a fully functional FreeBSD

2.1.0 or later system for the package to work!</para>

2.1.0 or later system for the package to work!</para>

<variablelist>

<variablelist>

<varlistentry><term><acronym>BASIC</></term>

<varlistentry><term><acronym>BASIC</></term>

</varlistentry>

</varlistentry>

</variablelist>

</variablelist>

</sect2>

</sect2>

<para>Fortunately, almost all this detail is hidden from you, as

<para>Fortunately, almost all this detail is hidden from you, as

<command>cc</> is a front end that manages calling all these programs

<command>cc</> is a front end that manages calling all these programs

with the right arguments for you; simply typing

with the right arguments for you; simply typing

<para>will cause <filename>foobar.c</> to be compiled by all the

<para>will cause <filename>foobar.c</> to be compiled by all the

steps above. If you have more than one file to compile, just do

steps above. If you have more than one file to compile, just do

something like

something like

</para>

</para>

<para>Note that the syntax checking is just that&mdash;checking the

<para>Note that the syntax checking is just that&mdash;checking the

syntax. It will not check for any logical mistakes you may have made,

syntax. It will not check for any logical mistakes you may have made,

the mists of history.</para></footnote></para>

the mists of history.</para></footnote></para>

<informalexample>

<informalexample>

</informalexample>

</informalexample>

</listitem>

</listitem>

</varlistentry>

</varlistentry>

a <filename>Makefile</filename>.</para>

a <filename>Makefile</filename>.</para>

<informalexample>

<informalexample>

</informalexample>

</informalexample>

<para>This will produce an <firstterm>object file</> (not an

<para>This will produce an <firstterm>object file</> (not an

works properly.</para>

works properly.</para>

<informalexample>

<informalexample>

</informalexample>

</informalexample>

<para>This will produce a debug version of the

<para>This will produce a debug version of the

version.</para>

version.</para>

<informalexample>

<informalexample>

</informalexample>

</informalexample>

<para>This will produce an optimised version of

<para>This will produce an optimised version of

what you may be using in a few years time?</para>

what you may be using in a few years time?</para>

<informalexample>

<informalexample>

</informalexample>

</informalexample>

<para>This will produce an executable <filename>foobar</filename>

<para>This will produce an executable <filename>foobar</filename>

last library on the command line.</para>

last library on the command line.</para>

<informalexample>

<informalexample>

</informalexample>

</informalexample>

<para>This will link the math library functions into

<para>This will link the math library functions into

on FreeBSD.</para>

on FreeBSD.</para>

<informalexample>

<informalexample>

</informalexample>

</informalexample>

<para>Each of these will both produce an executable

<para>Each of these will both produce an executable

<sect2>

<sect2>

<title>Common <command>cc</command> Queries and Problems</title>

<title>Common <command>cc</command> Queries and Problems</title>

<function>sin()</function> function and I get an error like this.

<function>sin()</function> function and I get an error like this.

What does it mean?

What does it mean?

<informalexample>

<informalexample>

<screen>/var/tmp/cc0143941.o: Undefined symbol `_sin' referenced from text segment</screen>

<screen>/var/tmp/cc0143941.o: Undefined symbol `_sin' referenced from text segment</screen>

</informalexample>

</informalexample>

<function>sin()</function>, you have to tell <command>cc</command> to

<function>sin()</function>, you have to tell <command>cc</command> to

<informalexample>

<informalexample>

<option>-lm</option>. All it does is raise 2.1 to the power of 6.

<option>-lm</option>. All it does is raise 2.1 to the power of 6.

<informalexample>

<informalexample>

<programlisting>#include &lt;stdio.h&gt;

<programlisting>#include &lt;stdio.h&gt;

	return 0;

	return 0;

}</programlisting>

}</programlisting>

</informalexample>

</informalexample>

and I compiled it as:

and I compiled it as:

<informalexample>

<informalexample>

</informalexample>

</informalexample>

like you said I should, but I get this when I run it:

like you said I should, but I get this when I run it:

<informalexample>

<informalexample>

2.1 ^ 6 = 1023.000000</screen>

2.1 ^ 6 = 1023.000000</screen>

</informalexample>

</informalexample>

<para>This is <emphasis>not</emphasis> the right answer! What is

<para>This is <emphasis>not</emphasis> the right answer! What is

going on?</para>

going on?</para>

has already seen a prototype for it. If it has not, it assumes the

has already seen a prototype for it. If it has not, it assumes the

function returns an <type>int</type>, which is

function returns an <type>int</type>, which is

definitely not what you want here.</para>

definitely not what you want here.</para>

<filename>math.h</filename>. If you include this file, the compiler

<filename>math.h</filename>. If you include this file, the compiler

will be able to find the prototype and it will stop doing strange

will be able to find the prototype and it will stop doing strange

things to your calculation!

things to your calculation!

<informalexample>

<informalexample>

<programlisting>#include &lt;math.h&gt;

<programlisting>#include &lt;math.h&gt;

#include <stdio.h>

#include <stdio.h>

int main() {

int main() {

...</programlisting>

...</programlisting>

</informalexample>

</informalexample>

<para>After recompiling it as you did before, run it:

<para>After recompiling it as you did before, run it:

<informalexample>

<informalexample>

2.1 ^ 6 = 85.766121</screen>

2.1 ^ 6 = 85.766121</screen>

</informalexample>

</informalexample>

<para>If you are using any of the mathematical functions,

<para>If you are using any of the mathematical functions,

<emphasis>always</emphasis> include <filename>math.h</filename> and

<emphasis>always</emphasis> include <filename>math.h</filename> and

remember to link in the math library.</para>

remember to link in the math library.</para>

cannot find an executable called <filename>foobar</filename>. Where's

cannot find an executable called <filename>foobar</filename>. Where's

it gone?</para>

it gone?</para>

<filename>a.out</filename> unless you tell it differently. Use the

<filename>a.out</filename> unless you tell it differently. Use the

<option>-o&nbsp;<replaceable>filename</replaceable></option> option:

<option>-o&nbsp;<replaceable>filename</replaceable></option> option:

<informalexample>

<informalexample>

</informalexample>

</informalexample>

I can see it when I run <command>ls</command>, but when I type in

I can see it when I run <command>ls</command>, but when I type in

<command>foobar</command> at the command prompt it tells me there is

<command>foobar</command> at the command prompt it tells me there is

no such file. Why can it not find it?</para>

no such file. Why can it not find it?</para>

current directory when it is trying to find out which executable you

current directory when it is trying to find out which executable you

want it to run, unless you tell it to. Either type

want it to run, unless you tell it to. Either type

<command>./foobar</command>, which means <quote>run the file called

<command>./foobar</command>, which means <quote>run the file called

<filename>foobar</filename> in the current directory</quote>, or

<filename>foobar</filename> in the current directory</quote>, or

change your <systemitem class=environvar>PATH</systemitem>

change your <systemitem class=environvar>PATH</systemitem>

environment variable so that it looks something like

environment variable so that it looks something like

<informalexample>

<informalexample>

<screen>bin:/usr/bin:/usr/local/bin:.</screen>

<screen>bin:/usr/bin:/usr/local/bin:.</screen>

</informalexample>

</informalexample>

The dot at the end means <quote>look in the current directory if it is not in

The dot at the end means <quote>look in the current directory if it is not in

any of the others</quote>.</para>

any of the others</quote>.</para>

nothing happens when I run it. What is going on?</para>

nothing happens when I run it. What is going on?</para>

<command>test</command> in <filename>/usr/bin</filename> and the

<command>test</command> in <filename>/usr/bin</filename> and the

shell is picking that one up before it gets to checking the current

shell is picking that one up before it gets to checking the current

directory. Either type:

directory. Either type:

<informalexample>

<informalexample>

</informalexample>

</informalexample>

or choose a better name for your program!</para>

or choose a better name for your program!</para>

first, then there was an error and it said something about <errorname>core

first, then there was an error and it said something about <errorname>core

dumped</errorname>. What does that mean?</para>

dumped</errorname>. What does that mean?</para>

very early days of Unix, when the machines used core memory for

very early days of Unix, when the machines used core memory for

storing data. Basically, if the program failed under certain

storing data. Basically, if the program failed under certain

conditions, the system would write the contents of core memory to

conditions, the system would write the contents of core memory to

disk in a file called <filename>core</filename>, which the programmer

disk in a file called <filename>core</filename>, which the programmer

could then pore over to find out what went wrong.</para>

could then pore over to find out what went wrong.</para>

linkend="debugging">).</para>

linkend="debugging">).</para>

<errorname>segmentation fault</errorname>. What's that?</para>

<errorname>segmentation fault</errorname>. What's that?</para>

of illegal operation on memory; Unix is designed to protect the

of illegal operation on memory; Unix is designed to protect the

operating system and other programs from rogue programs.</para>

operating system and other programs from rogue programs.</para>

<para>Common causes for this are:

<para>Common causes for this are:

<itemizedlist>

<itemizedlist>

<listitem><para>Trying to write to a <symbol>NULL</symbol> pointer, eg

<listitem><para>Trying to write to a <symbol>NULL</symbol> pointer, eg

<programlisting>char *foo = NULL;

<programlisting>char *foo = NULL;

strcpy(foo, "bang!");</programlisting>

strcpy(foo, "bang!");</programlisting>

<listitem><para>Using a pointer that hasn't been initialised, eg

<listitem><para>Using a pointer that hasn't been initialised, eg

<programlisting>char *foo;

<programlisting>char *foo;

strcpy(foo, "bang!");</programlisting>

strcpy(foo, "bang!");</programlisting>

The pointer will have some random value that, with luck,

The pointer will have some random value that, with luck,

will point into an area of memory that isn't available to

will point into an area of memory that isn't available to

your program and the kernel will kill your program before

your program and the kernel will kill your program before

mysteriously.</para></listitem>

mysteriously.</para></listitem>

<listitem><para>Trying to access past the end of an array, eg

<listitem><para>Trying to access past the end of an array, eg

<programlisting>int bar[20];

<programlisting>int bar[20];

<listitem><para> Trying to store something in read-only memory, eg

<listitem><para> Trying to store something in read-only memory, eg

<programlisting>char *foo = "My string";

<programlisting>char *foo = "My string";

strcpy(foo, "bang!");</programlisting>

strcpy(foo, "bang!");</programlisting>

Unix compilers often put string literals like

Unix compilers often put string literals like

<literal>"My string"</literal> into

<literal>"My string"</literal> into

read-only areas of memory.</para></listitem>

read-only areas of memory.</para></listitem>

<listitem><para>Doing naughty things with

<listitem><para>Doing naughty things with

<function>malloc()</function> and <function>free()</function>, eg

<function>malloc()</function> and <function>free()</function>, eg

<programlisting>char bar[80];

<programlisting>char bar[80];

free(bar);</programlisting>

free(bar);</programlisting>

or

or

<programlisting>char *foo = malloc(27);

<programlisting>char *foo = malloc(27);

free(foo);

free(foo);

free(foo);</programlisting>

free(foo);</programlisting>

<para>Making one of these mistakes will not always lead to an

<para>Making one of these mistakes will not always lead to an

error, but they are always bad practice. Some systems and

error, but they are always bad practice. Some systems and

compilers are more tolerant than others, which is why programs

compilers are more tolerant than others, which is why programs

that ran well on one system can crash when you try them on an

that ran well on one system can crash when you try them on an

another.</para>

another.</para>

error</errorname>. It says in my Unix book that this means a hardware

error</errorname>. It says in my Unix book that this means a hardware

problem, but the computer still seems to be working. Is this

problem, but the computer still seems to be working. Is this

true?</para>

true?</para>

problem…). This is usually another way of saying that you

problem…). This is usually another way of saying that you

accessed memory in a way you shouldn't have.</para>

accessed memory in a way you shouldn't have.</para>

useful, if I can make it happen when I want to. Can I do this, or

useful, if I can make it happen when I want to. Can I do this, or

do I have to wait until there's an error?</para>

do I have to wait until there's an error?</para>

to find out the process ID of your program, and do

to find out the process ID of your program, and do

where <parameter><replaceable>pid</replaceable></parameter> is the

where <parameter><replaceable>pid</replaceable></parameter> is the

process ID you looked up.</para>

process ID you looked up.</para>

loop, for instance. If your program happens to trap

loop, for instance. If your program happens to trap

<symbol>SIGABRT</symbol>, there are several other signals which have

<symbol>SIGABRT</symbol>, there are several other signals which have

a similar effect.</para>

a similar effect.</para>

</sect2>

</sect2>

</sect1>

</sect1>

<para>When you're working on a simple program with only one or two source

<para>When you're working on a simple program with only one or two source

files, typing in

files, typing in

is not too bad, but it quickly becomes very tedious when there are

is not too bad, but it quickly becomes very tedious when there are

several files&mdash;and it can take a while to compile, too.</para>

several files&mdash;and it can take a while to compile, too.</para>

<para>One way to get around this is to use object files and only recompile

<para>One way to get around this is to use object files and only recompile

the source file if the source code has changed. So we could have

the source file if the source code has changed. So we could have

something like:

something like:

if we'd changed <filename>file37.c</filename>, but not any of the

if we'd changed <filename>file37.c</filename>, but not any of the

others, since the last time we compiled.  This may speed up the

others, since the last time we compiled.  This may speed up the

compilation quite a bit, but  doesn't solve the typing

compilation quite a bit, but  doesn't solve the typing

<title>Example of using <command>make</command></title>

<title>Example of using <command>make</command></title>

<para>Here's a very simple make file:

<para>Here's a very simple make file:

<programlisting>foo: foo.c

<programlisting>foo: foo.c

	cc -o foo foo.c</programlisting>

	cc -o foo foo.c</programlisting>

It consists of two lines, a dependency line and a creation line.</para>

It consists of two lines, a dependency line and a creation line.</para>

<para>The dependency line here consists of the name of the program

<para>The dependency line here consists of the name of the program

<para>Another useful property of makefiles is that the targets don't have

<para>Another useful property of makefiles is that the targets don't have

to be programs. For instance, we could have a make file that looks

to be programs. For instance, we could have a make file that looks

like this:

like this:

<programlisting>foo: foo.c

<programlisting>foo: foo.c

	cc -o foo foo.c

	cc -o foo foo.c

install:

install:

<para>We can tell make which target we want to make by typing:

<para>We can tell make which target we want to make by typing:

<command>make</command> will then only look at that target and ignore any

<command>make</command> will then only look at that target and ignore any

others. For example, if we type <userinput>make foo</userinput> with the 

others. For example, if we type <userinput>make foo</userinput> with the 

makefile above, make will ignore the <action>install</action> target.</para>

makefile above, make will ignore the <action>install</action> target.</para>

BSD-based systems like FreeBSD come with some very powerful ones as

BSD-based systems like FreeBSD come with some very powerful ones as

part of the system.  One very good example of this is the FreeBSD

part of the system.  One very good example of this is the FreeBSD

ports system. Here's the essential part of a typical ports

ports system. Here's the essential part of a typical ports

<programlisting>MASTER_SITES=   ftp://freefall.cdrom.com/pub/FreeBSD/LOCAL_PORTS/

<programlisting>MASTER_SITES=   ftp://freefall.cdrom.com/pub/FreeBSD/LOCAL_PORTS/

DISTFILES=      scheme-microcode+dist-7.3-freebsd.tgz

DISTFILES=      scheme-microcode+dist-7.3-freebsd.tgz

<para>Now, if we go to the directory for this port and type

<para>Now, if we go to the directory for this port and type

<userinput>make</userinput>, the following happens:</para>

<userinput>make</userinput>, the following happens:</para>

<para>The version of make that comes with FreeBSD is the <application>Berkeley

<para>The version of make that comes with FreeBSD is the <application>Berkeley

make</application>; there is a tutorial for it in

make</application>; there is a tutorial for it in

<filename>/usr/share/doc/psd/12.make</filename>. To view it, do

<filename>/usr/share/doc/psd/12.make</filename>. To view it, do

in that directory.</para>

in that directory.</para>

<para>Many applications in the ports use <application>GNU

<para>Many applications in the ports use <application>GNU

you will have to edit the <filename>dir</filename> file in the

you will have to edit the <filename>dir</filename> file in the

<filename>/usr/local/info</filename> directory to add an entry for

<filename>/usr/local/info</filename> directory to add an entry for

it. This involves adding a line like

it. This involves adding a line like

<programlisting> * Make: (make).                 The GNU Make utility.</programlisting>

<programlisting> * Make: (make).                 The GNU Make utility.</programlisting>

to the file. Once you have done this, you can type

to the file. Once you have done this, you can type

<userinput>info</userinput> and then select

<userinput>info</userinput> and then select

<guimenuitem>make</guimenuitem> from the menu (or in

<guimenuitem>make</guimenuitem> from the menu (or in

<para>The debugger that comes with FreeBSD is called

<para>The debugger that comes with FreeBSD is called

<command>gdb</command> (<application>GNU

<command>gdb</command> (<application>GNU

debugger</application>). You start it up by typing

debugger</application>). You start it up by typing

although most people prefer to run it inside

although most people prefer to run it inside

<application>Emacs</application>. You can do this by:

<application>Emacs</application>. You can do this by:

<para>Using a debugger allows you to run the program under more

<para>Using a debugger allows you to run the program under more

controlled circumstances. Typically, you can step through the program

controlled circumstances. Typically, you can step through the program

<command>gdb</command>. It will work without, but you'll only see the

<command>gdb</command>. It will work without, but you'll only see the

name of the function you're in, instead of the source code. If you

name of the function you're in, instead of the source code. If you

see a line like:

see a line like:

<command>gdb</command> starts up, you'll know that the program wasn't

<command>gdb</command> starts up, you'll know that the program wasn't

compiled with the <option>-g</option> option.</para>

compiled with the <option>-g</option> option.</para>

<para>Here's a simple example of how to spot a mistake in a program

<para>Here's a simple example of how to spot a mistake in a program

with <command>gdb</command>. This is our program (with a deliberate

with <command>gdb</command>. This is our program (with a deliberate

mistake):

mistake):

<programlisting>#include &lt;stdio.h&gt;

<programlisting>#include &lt;stdio.h&gt;

int bazz(int anint);

int bazz(int anint);

	printf("You gave me %d\n", anint);

	printf("You gave me %d\n", anint);

	return anint;

	return anint;

}</programlisting>

}</programlisting>

<para>This program sets <symbol>i</symbol> to be <literal>5</literal>

<para>This program sets <symbol>i</symbol> to be <literal>5</literal>

and passes it to a function <function>bazz()</function> which prints

and passes it to a function <function>bazz()</function> which prints

out the number we gave it.</para>

out the number we gave it.</para>

<para>When we compile and run the program we get

<para>When we compile and run the program we get

This is my program

This is my program

<para>That wasn't what we expected! Time to see what's going

<para>That wasn't what we expected! Time to see what's going

GDB is free software and you are welcome to distribute copies of it

GDB is free software and you are welcome to distribute copies of it

 under certain conditions; type "show copying" to see the conditions.

 under certain conditions; type "show copying" to see the conditions.

There is absolutely no warranty for GDB; type "show warranty" for details.

There is absolutely no warranty for GDB; type "show warranty" for details.

This is my program				<lineannotation>Program prints out</>

This is my program				<lineannotation>Program prints out</>

(gdb) <userinput>s</>						<lineannotation>step into <function>bazz()</></>

(gdb) <userinput>s</>						<lineannotation>step into <function>bazz()</></>

bazz (anint=4231) at temp.c:17			<lineannotation><command>gdb</command> displays stack frame</>

bazz (anint=4231) at temp.c:17			<lineannotation><command>gdb</command> displays stack frame</>

<para>Hang on a minute! How did <symbol>anint</symbol> get to be

<para>Hang on a minute! How did <symbol>anint</symbol> get to be

in <function>main()</function>? Let's move up to

in <function>main()</function>? Let's move up to

<function>main()</function> and have a look.</para>

<function>main()</function> and have a look.</para>

#1  0x1625 in main () at temp.c:11		<lineannotation><command>gdb</command> displays stack frame</>

#1  0x1625 in main () at temp.c:11		<lineannotation><command>gdb</command> displays stack frame</>

(gdb) <userinput>p i</>					<lineannotation>Show us the value of <symbol>i</></>

(gdb) <userinput>p i</>					<lineannotation>Show us the value of <symbol>i</></>

Oh dear! Looking at the code, we forgot to initialise

Oh dear! Looking at the code, we forgot to initialise

<symbol>i</symbol>. We meant to put

<symbol>i</symbol>. We meant to put

<programlisting><lineannotation>&hellip;</>

<programlisting><lineannotation>&hellip;</>

main() {

main() {

	int i;

	int i;

	i = 5;

	i = 5;

	printf("This is my program\n");

	printf("This is my program\n");

<lineannotation>&hellip</></programlisting>

<lineannotation>&hellip</></programlisting>

but we left the <literal>i=5;</literal> line out.  As we didn't

but we left the <literal>i=5;</literal> line out.  As we didn't

initialise <symbol>i</symbol>, it had whatever number happened to be

initialise <symbol>i</symbol>, it had whatever number happened to be

in that area of memory when the program ran, which in this case

in that area of memory when the program ran, which in this case

<para>To examine a core file, start up <command>gdb</command> in the

<para>To examine a core file, start up <command>gdb</command> in the

usual way. Instead of typing <command>break</command> or

usual way. Instead of typing <command>break</command> or

<command>run</command>, type

<command>run</command>, type

<screen>(gdb) <userinput>core <replaceable>progname</replaceable>.core</userinput></screen>

<screen>(gdb) <userinput>core <replaceable>progname</replaceable>.core</userinput></screen>

If you're not in the same directory as the core file, you'll have to

If you're not in the same directory as the core file, you'll have to

do <userinput>dir /path/to/core/file</userinput> first.</para>

do <userinput>dir /path/to/core/file</userinput> first.</para>

<para>You should see something like this:

<para>You should see something like this:

GDB is free software and you are welcome to distribute copies of it

GDB is free software and you are welcome to distribute copies of it

 under certain conditions; type "show copying" to see the conditions.

 under certain conditions; type "show copying" to see the conditions.

There is absolutely no warranty for GDB; type "show warranty" for details.

There is absolutely no warranty for GDB; type "show warranty" for details.

Program terminated with signal 11, Segmentation fault.

Program terminated with signal 11, Segmentation fault.

Cannot access memory at address 0x7020796d.

Cannot access memory at address 0x7020796d.

#0  0x164a in bazz (anint=0x5) at temp.c:17

#0  0x164a in bazz (anint=0x5) at temp.c:17

<para>In this case, the program was called

<para>In this case, the program was called

<filename>a.out</filename>, so the core file is called

<filename>a.out</filename>, so the core file is called

stack in a complex program. The <command>bt</command> command causes

stack in a complex program. The <command>bt</command> command causes

<command>gdb</command> to print out a back-trace of the call

<command>gdb</command> to print out a back-trace of the call

stack:

stack:

<screen>(gdb) <userinput>bt</userinput>

<screen>(gdb) <userinput>bt</userinput>

#0  0x164a in bazz (anint=0x5) at temp.c:17

#0  0x164a in bazz (anint=0x5) at temp.c:17

#1  0xefbfd888 in end ()

#1  0xefbfd888 in end ()

#2  0x162c in main () at temp.c:11

#2  0x162c in main () at temp.c:11

a program crashes; in this case, the <function>bazz()</function>

a program crashes; in this case, the <function>bazz()</function>

function was called from <function>main()</function>.</para>

function was called from <function>main()</function>.</para>

<para>What you do is start up another <command>gdb</command>, use

<para>What you do is start up another <command>gdb</command>, use

<command>ps</command> to find the process ID for the child, and

<command>ps</command> to find the process ID for the child, and

in <command>gdb</command>, and then debug as usual.</para>

in <command>gdb</command>, and then debug as usual.</para>

<para><quote>That's all very well,</quote> you're probably thinking,

<para><quote>That's all very well,</quote> you're probably thinking,

<quote>but by the time I've done that, the child process will be over

<quote>but by the time I've done that, the child process will be over

the hill and far away</quote>. Fear not, gentle reader, here's how to

the hill and far away</quote>. Fear not, gentle reader, here's how to

do it (courtesy of the <command>gdb</command> info pages):

do it (courtesy of the <command>gdb</command> info pages):

<screen><lineannotation>&hellip</lineannotation>

<screen><lineannotation>&hellip</lineannotation>

if ((pid = fork()) < 0)		/* _Always_ check this */

if ((pid = fork()) < 0)		/* _Always_ check this */

	error();

	error();

	<lineannotation>&hellip</lineannotation>

	<lineannotation>&hellip</lineannotation>

} else {			/* parent */

} else {			/* parent */

	<lineannotation>&hellip</lineannotation></screen>

	<lineannotation>&hellip</lineannotation></screen>

Now all you have to do is attach to the child, set

Now all you have to do is attach to the child, set

<symbol>PauseMode</symbol> to <literal>0</literal>, and

<symbol>PauseMode</symbol> to <literal>0</literal>, and

wait for the <function>sleep()</function> call to return!</para>

wait for the <function>sleep()</function> call to return!</para>

<para>It's impossible even to summarise everything Emacs can do here, but

<para>It's impossible even to summarise everything Emacs can do here, but

here are some of the features of interest to developers:

here are some of the features of interest to developers:

<itemizedlist>

<itemizedlist>

<listitem><para>Very powerful editor, allowing search-and-replace on

<listitem><para>Very powerful editor, allowing search-and-replace on

<listitem><para>You can read Usenet news and mail while your program

<listitem><para>You can read Usenet news and mail while your program

is compiling.</para></listitem>

is compiling.</para></listitem>

<para>Emacs can be installed on FreeBSD using <ulink

<para>Emacs can be installed on FreeBSD using <ulink

URL="../../ports/editors.html">the Emacs

URL="../../ports/editors.html">the Emacs

<para>Unfortunately, there's far too much here to explain it in detail;

<para>Unfortunately, there's far too much here to explain it in detail;

however there are one or two points worth mentioning.</para>

however there are one or two points worth mentioning.</para>

<itemizedlist>

<itemizedlist>

<listitem><para>Everything beginning with a <literal>;</> is a

<listitem><para>Everything beginning with a <literal>;</> is a

<listitem><para> We enable Emacs's ability to act as a server, so

<listitem><para> We enable Emacs's ability to act as a server, so

that if you're doing something outside Emacs and you want to edit a

that if you're doing something outside Emacs and you want to edit a

file, you can just type in 

file, you can just type in 

and then you can edit the file in your Emacs!<footnote><para>Many

and then you can edit the file in your Emacs!<footnote><para>Many

Emacs users set their <systemitem

Emacs users set their <systemitem

class=environvar>EDITOR</systemitem> environment to

class=environvar>EDITOR</systemitem> environment to

to edit a file.</para></footnote></para></listitem>

to edit a file.</para></footnote></para></listitem>

</itemizedlist>

</itemizedlist>

<example>

<example>

<title>A sample <filename>.emacs</filename> file</title>

<title>A sample <filename>.emacs</filename> file</title>

;; This file is designed to be re-evaled; use the variable first-time

;; This file is designed to be re-evaled; use the variable first-time

;; to avoid any problems with this.

;; to avoid any problems with this.

(autoload 'ediff-buffers "ediff" "Intelligent Emacs interface to diff" t)

(autoload 'ediff-buffers "ediff" "Intelligent Emacs interface to diff" t)

(autoload 'ediff-files "ediff" "Intelligent Emacs interface to diff" t)

(autoload 'ediff-files "ediff" "Intelligent Emacs interface to diff" t)

(autoload 'ediff-files-remote "ediff"

(autoload 'ediff-files-remote "ediff"

    (setq auto-mode-alist

    (setq auto-mode-alist

	  (append '(("\\.cpp$" . c++-mode)

	  (append '(("\\.cpp$" . c++-mode)

		    ("\\.hpp$" . c++-mode)

		    ("\\.hpp$" . c++-mode)

(defun previous-error (n)

(defun previous-error (n)

  "Visit previous compilation error message and corresponding source code."

  "Visit previous compilation error message and corresponding source code."

  (interactive "p")

  (interactive "p")

(transient-mark-mode 1)

(transient-mark-mode 1)

(setq mark-even-if-inactive t)

(setq mark-even-if-inactive t)

(setq visible-bell nil)

(setq visible-bell nil)

;; All done

;; All done

(message "All done, %s%s" (user-login-name) ".")

(message "All done, %s%s" (user-login-name) ".")

</example>

</example>

</sect2>

</sect2>

usually end in <filename>.el</filename>, short for <quote>Emacs

usually end in <filename>.el</filename>, short for <quote>Emacs

Lisp</quote>. For example, if whizbang is a FreeBSD

Lisp</quote>. For example, if whizbang is a FreeBSD

port, we can locate these files by doing

port, we can locate these files by doing

and install them by copying them into the Emacs site Lisp directory. On

and install them by copying them into the Emacs site Lisp directory. On

FreeBSD 2.1.0-RELEASE, this is

FreeBSD 2.1.0-RELEASE, this is

<filename>/usr/local/share/emacs/site-lisp</filename>.</para>

<filename>/usr/local/share/emacs/site-lisp</filename>.</para>

<para>So for example, if the output from the find command was

<para>So for example, if the output from the find command was

<screen>/usr/ports/lang/whizbang/work/misc/whizbang.el</screen>

<screen>/usr/ports/lang/whizbang/work/misc/whizbang.el</screen>

we would do

we would do

</para>

</para>

<para>Next, we need to decide what extension whizbang source files

<para>Next, we need to decide what extension whizbang source files

have. Let's say for the sake of argument that they all end in

have. Let's say for the sake of argument that they all end in

<para>Find the <symbol>auto-mode-alist entry</symbol> in

<para>Find the <symbol>auto-mode-alist entry</symbol> in

<filename>.emacs</filename> and add a line for whizbang, such

<filename>.emacs</filename> and add a line for whizbang, such

as:

as:

<programlisting><lineannotation>&hellip;</>

<programlisting><lineannotation>&hellip;</>

("\\.lsp$" . lisp-mode)

("\\.lsp$" . lisp-mode)

("\\.wiz$" . whizbang-mode)

("\\.wiz$" . whizbang-mode)

("\\.scm$" . scheme-mode)

("\\.scm$" . scheme-mode)

<lineannotation>&hellip;</></programlisting>  

<lineannotation>&hellip;</></programlisting>  

This means that Emacs will automatically go into

This means that Emacs will automatically go into

<function>whizbang-mode</function> when you edit a file ending in

<function>whizbang-mode</function> when you edit a file ending in

<filename>.wiz</filename>.</para>

<filename>.wiz</filename>.</para>

<para>Just below this, you'll find the

<para>Just below this, you'll find the

<symbol>font-lock-auto-mode-list</symbol> entry. Add

<symbol>font-lock-auto-mode-list</symbol> entry. Add

<function>whizbang-mode</function> to it like so:

<function>whizbang-mode</function> to it like so:

<programlisting>;; Auto font lock mode

<programlisting>;; Auto font lock mode

(defvar font-lock-auto-mode-list 

(defvar font-lock-auto-mode-list 

  (list 'c-mode 'c++-mode 'c++-c-mode 'emacs-lisp-mode 'whizbang-mode 'lisp-mode 'perl-mode 'scheme-mode)

  (list 'c-mode 'c++-mode 'c++-c-mode 'emacs-lisp-mode 'whizbang-mode 'lisp-mode 'perl-mode 'scheme-mode)

  "List of modes to always start in font-lock-mode")</programlisting>

  "List of modes to always start in font-lock-mode")</programlisting>

This means that Emacs will always enable

This means that Emacs will always enable

<function>font-lock-mode</function> (ie syntax highlighting) when

<function>font-lock-mode</function> (ie syntax highlighting) when

editing a <filename>.wiz</filename> file.</para>

editing a <filename>.wiz</filename> file.</para>