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--- ---
title: Chapter 2. Programming Tools title: Chapter 2. Programming Tools
authors: authors:
- author: James Raynard - author: James Raynard
- author: Murray Stokely - author: Murray Stokely
prev: books/developers-handbook/introduction prev: books/developers-handbook/introduction
next: books/developers-handbook/secure next: books/developers-handbook/secure
description: Programming Tools description: Programming Tools
tags: ["tools", "Interpreters", "Compilers", "cc", "make", "Debugging", "lldb", "gdb", "Emacs"] tags: ["tools", "Interpreters", "Compilers", "cc", "make", "Debugging", "lldb", "gdb", "clang", "Emacs"]
--- ---
[[tools]] [[tools]]
= Programming Tools = Programming Tools
:doctype: book :doctype: book
:toc: macro :toc: macro
:toclevels: 1 :toclevels: 1
:icons: font :icons: font
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As the edit-compile-run-debug cycle is rather tedious when using separate programs, many commercial compiler makers have produced Integrated Development Environments (IDEs for short). As the edit-compile-run-debug cycle is rather tedious when using separate programs, many commercial compiler makers have produced Integrated Development Environments (IDEs for short).
FreeBSD does not include an IDE in the base system, but package:devel/kdevelop[] is available in the Ports Collection and many use Emacs for this purpose. FreeBSD does not include an IDE in the base system, but package:devel/kdevelop[] is available in the Ports Collection and many use Emacs for this purpose.
Using Emacs as an IDE is discussed in <<emacs>>. Using Emacs as an IDE is discussed in <<emacs>>.
[[tools-compiling]] [[tools-compiling]]
== Compiling with `cc` == Compiling with `cc`
This section deals with the gcc and clang compilers for C and C++, since they come with the FreeBSD base system. This section deals with the clang compiler for C and C++, as it's installed with the FreeBSD base system.
Starting with FreeBSD 10.X `clang` is installed as `cc`. Starting with FreeBSD 10.X `clang` is installed as `cc`; the GNU compiler package:devel/gcc[gcc] is available in the Ports Collection.
The details of producing a program with an interpreter vary considerably between interpreters, and are usually well covered in the documentation and on-line help for the interpreter. The details of producing a program with an interpreter vary considerably between interpreters, and are usually well covered in the documentation and on-line help for the interpreter.
Once you have written your masterpiece, the next step is to convert it into something that will (hopefully!) run on FreeBSD. Once you have written your masterpiece, the next step is to convert it into something that will (hopefully!) run on FreeBSD.
This usually involves several steps, each of which is done by a separate program. This usually involves several steps, each of which is done by a separate program.
[.procedure] [.procedure]
. Pre-process your source code to remove comments and do other tricks like expanding macros in C. . Pre-process your source code to remove comments and do other tricks like expanding macros in C.
. Check the syntax of your code to see if you have obeyed the rules of the language. If you have not, it will complain! . Check the syntax of your code to see if you have obeyed the rules of the language. If you have not, it will complain!
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will cause [.filename]#foobar.c# to be compiled by all the steps above. will cause [.filename]#foobar.c# to be compiled by all the steps above.
If you have more than one file to compile, just do something like If you have more than one file to compile, just do something like
[source,bash] [source,bash]
.... ....
% cc foo.c bar.c % cc foo.c bar.c
.... ....
Note that the syntax checking is just that-checking the syntax. Note that the syntax checking is just that - checking the syntax.
It will not check for any logical mistakes you may have made, like putting the program into an infinite loop, It will not check for any logical mistakes you may have made, like putting the program into an infinite loop,
or using a bubble sort when you meant to use a binary sort.footnote:[In case you did not know, a binary sort is an efficient way of sorting things into order and a bubble sort is not.] or using a bubble sort when you meant to use a binary sort.footnote:[In case you did not know, a binary sort is an efficient way of sorting things into order and a bubble sort is not.]
There are lots and lots of options for `cc`, which are all in the manual page. There are lots and lots of options for `cc`, which are all in the manual page.
Here are a few of the most important ones, with examples of how to use them. Here are a few of the most important ones, with examples of how to use them.
`-o _filename_`:: `-o _filename_`::
The output name of the file. If you do not use this option, `cc` will produce an executable called [.filename]#a.out#.footnote:[The reasons for this are buried in the mists of history.] The output name of the file. If you do not use this option, `cc` will produce an executable called [.filename]#a.out#.footnote:[The reasons for this are buried in the mists of history.]
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`-ansi`:: `-ansi`::
Turn off most, but not all, of the non-ANSI C features provided by `cc`. Turn off most, but not all, of the non-ANSI C features provided by `cc`.
Despite the name, it does not guarantee strictly that your code will comply to the standard. Despite the name, it does not guarantee strictly that your code will comply to the standard.
`-pedantic`:: `-pedantic`::
Turn off _all_ ``cc``'s non-ANSI C features. Turn off _all_ ``cc``'s non-ANSI C features.
Without these flags, `cc` will allow you to use some of its non-standard extensions to the standard. Without these flags, `cc` will allow you to use some of its non-standard extensions to the standard.
Some of these are very useful, but will not work with other compilers-in fact, Some of these are very useful, but will not work with other compilers - in fact,
one of the main aims of the standard is to allow people to write code that will work with any compiler on any system. one of the main aims of the standard is to allow people to write code that will work with any compiler on any system.
This is known as _portable code_. This is known as _portable code_.
Generally, you should try to make your code as portable as possible, Generally, you should try to make your code as portable as possible,
as otherwise you may have to completely rewrite the program later to get it to work somewhere else-and who knows what you may be using in a few years time? as otherwise you may have to completely rewrite the program later to get it to work somewhere else - and who knows what you may be using in a few years time?
[source,bash] [source,bash]
.... ....
% cc -Wall -ansi -pedantic -o foobar foobar.c % cc -Wall -ansi -pedantic -o foobar foobar.c
.... ....
This will produce an executable [.filename]#foobar# after checking [.filename]#foobar.c# for standard compliance. This will produce an executable [.filename]#foobar# after checking [.filename]#foobar.c# for standard compliance.
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[source,bash] [source,bash]
.... ....
% c++ -o foobar foobar.cc % c++ -o foobar foobar.cc
.... ....
+ +
This will both produce an executable [.filename]#foobar# from the C++ source file [.filename]#foobar.cc#. This will both produce an executable [.filename]#foobar# from the C++ source file [.filename]#foobar.cc#.
=== Common `cc` Queries and Problems === Common `cc` Queries and Problems
==== I am trying to write a program which uses the sin() function and I get an error like this. What does it mean?
[source,bash]
....
/var/tmp/cc0143941.o: Undefined symbol `_sin' referenced from text segment
....
When using mathematical functions like `sin()`, you have to tell `cc` to link in the math library, like so:
[source,bash]
....
% cc -o foobar foobar.c -lm
....
==== All right, I wrote this simple program to practice using -lm. All it does is raise 2.1 to the power of 6.
[.programlisting]
....
#include <stdio.h>
int main() {
float f;
f = pow(2.1, 6);
printf("2.1 ^ 6 = %f\n", f);
return 0;
}
....
and I compiled it as:
[source,bash]
....
% cc temp.c -lm
....
like you said I should, but I get this when I run it:
[source,bash]
....
% ./a.out
2.1 ^ 6 = 1023.000000
....
This is not the right answer! What is going on?
When the compiler sees you call a function, it checks if it has already seen a prototype for it.
If it has not, it assumes the function returns an int, which is definitely not what you want here.
==== So how do I fix this?
The prototypes for the mathematical functions are in [.filename]#math.h#.
If you include this file, the compiler will be able to find the prototype and it will stop doing strange things to your calculation!
[.programlisting]
....
#include <math.h>
#include <stdio.h>
int main() {
...
....
After recompiling it as you did before, run it:
[source,bash]
....
% ./a.out
2.1 ^ 6 = 85.766121
....
If you are using any of the mathematical functions, _always_ include [.filename]#math.h# and remember to link in the math library.
==== I compiled a file called foobar.c and I cannot find an executable called foobar. Where has it gone? ==== I compiled a file called foobar.c and I cannot find an executable called foobar. Where has it gone?
Remember, `cc` will call the executable [.filename]#a.out# unless you tell it differently. Remember, `cc` will call the executable [.filename]#a.out# unless you tell it differently.
Use the `-o _filename_` option: Use the `-o _filename_` option:
[source,bash] [source,bash]
.... ....
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