Errata

Head First C

Errata for Head First C

Submit your own errata for this product.

The errata list is a list of errors and their corrections that were found after the product was released. If the error was corrected in a later version or reprint the date of the correction will be displayed in the column titled "Date Corrected".

The following errata were submitted by our customers and approved as valid errors by the author or editor.

Color key: Serious technical mistake Minor technical mistake Language or formatting error Typo Question Note Update

Version Location Description Submitted By Date submitted Date corrected
PDF
Page 9
item 3 using "./" to run object module

I am brand new to C. So I follow the book's instructions closely. I did not use the "./" in front of my compiled object module for Windows. I got a "module not found" message. Using "./" my module executed. I also found that it ran equally well with no ".exe" extension and with it. I am doing all this exclusively on my Windows 7, 64-bit laptop. My install was to C:\cygwin\

I am wondering if the cygwin version I installed is responsible for the difference. I installed the latest cygwin version 1.7.22 in November 2012.

Note from the Author or Editor:
Item 3 should say:

Run by typing cards on Windows, or ./cards on Mac, Linux and Cygwin.

 Tom Bullock  Dec 22, 2012  Jun 07, 2013
32
The Polite Guide to Standards

The option to compile to the C99 standard is -std=c99 not -std=99.

Note from the Author or Editor:
In "The Polite Guide to Standards" change "-std=99" to "-std=c99"

 Thomas Corbi?re  Aug 05, 2012  Jun 07, 2013
PDF
Page 37
while condition of Exercise Solution

The first time through the while loop the condition "card_name[0] != 'X'" is reading uninitialized memory, it could find any value there including 'X' (terminating the program before any input is accepted).

Note from the Author or Editor:
The bug is in the exercise on page 35/37.

The:

while(card_name[0] != 'X') {
...
printf("Current count: %i\n", count);
}

needs to be switched to a do/while loop:



do {
...
printf("Current count: %i\n", count);
} while(card_name[0] != 'X');

 Patrick Lahey  Jul 09, 2012  Jun 07, 2013
Printed
Page 46
Point 1,2 & 3 under section "C sends arguments as values"

In all the mentioned points, variable named 'longitude' is said to have the value 32. But actually it is the variable named latitude that has value of 32.

For example, Point 1 says :
"Initially, the main() function has a local variable called longitude that had value 32.

this should actually be :
"Initially, the main() function has a local variable called latitude that had value 32.

Note from the Author or Editor:
Throughout page 46, all references to "longitude" should say "latitude", and all references to "lon" should say "lat".

 Anupam Jain  Aug 15, 2012  Jun 07, 2013
67
sizeof(food) explanation

"(?/0? included)" should be change to "(?\0? included)".

Note from the Author or Editor:
In the annotation 1/3 of the way down the page change

'/0' included

to

'\0' included

 Thomas Corbi?re  Aug 06, 2012  Jun 07, 2013
88
What's my purpose? solution

The solution to the exercise is missing.

Note from the Author or Editor:
The blue-lines of the solution have gone missing from this page. They are available in the print editions. They should be put back on the page.

 Thomas Corbi?re  Aug 06, 2012  Jun 07, 2013
Printed
Page 91/93
Bottom left function

The line

fgets(search_for, 80, stdin)

Should be replaced by

scanf("%79s", search_for);

 Dawn Griffiths
Dawn Griffiths
 		 Jun 02, 2013  Jun 07, 2013
93
Annotation of the fourth solution

It's true that the solution is incorrect but I think that the main reason is that the parameters is not those expected by scanf() so the string length problem is irrelevant. Did you intend to write scanf("%80s", search_for)?

Note from the Author or Editor:
Replace:

scanf(search_for, 80, stdin)

with

scanf("%80s", search_for)

 Thomas Corbi?re  Aug 07, 2012  Jun 07, 2013
PDF
Page 94
Middle of page

The sample code for the jukebox application uses the "fgets" function to get the user's search string. However, fgets will add the newline (\n) character to the end of the string when the user presses the enter key to submit their search string. This newline character must be removed and replaced with the null character (\0) in order for it to actually match one of the song titles in the tracks[] array. Without replacing the newline character, the code as listed on this page does not work (however, the screenshot on the next page shows it functioning properly).

An example fix can be used directly after the following line:

fgets(search_for, 80, stdin);
// FIX TO REPLACE NEWLINE CHARACTER
if(search_for[strlen(search_for) - 1] == '\n') {
search_for[strlen(search_for) - 1] = '\0';
}

Note from the Author or Editor:
In the code on pages 91/93/94, each time the fgets() function is called, add the following line of code after it:

search_for[strlen(search_for) - 1] = '\0';

 Matthew Wilson  Jun 27, 2012  Jun 07, 2013
94
First annotation

"You still need to stdio.h" should be changed to "You still need stdio.h".

 Thomas Corbi?re  Aug 07, 2012  Jun 07, 2013
Printed
Page 94
Code in int main()

The line

fgets(search_for, 80, stdin)

Should be replaced by

scanf("%79s", search_for);

 Dawn Griffiths
Dawn Griffiths
 		 Jun 02, 2013  Jun 07, 2013
PDF
Page 113
Sidebar

1. Line 56 of the map.html file should read:

if ((lng < -180) || (lng > 180)) {

2. Google has invalidated the old API key used in the map.html file. A new v2 API key needs to be generated. The old API key appears on lines 12 and 16.

3. No instructions for how to get the map.html file were provided. The following works:

wget http://oreillyhfc.appspot.com/map.html
or
curl -C - -O http://oreillyhfc.appspot.com/map.html

Note from the Author or Editor:
This is a change needed on the website, not the book. No changes are needed for the book.

 BarryBrown  Sep 18, 2012 
Printed
Page 113
page 113

the link on page 113(http://oreillyhfc.appspot.com/map.html) was not working

Note from the Author or Editor:
Replace the link in the Do This with http://dogriffiths.github.io/HeadFirstC/map.html

 Anonymous  Aug 11, 2015 
128
1st paragraph

"then chances are you going" should be changed to "then chances are you're going".

 Thomas Corbi?re  Aug 07, 2012  Jun 07, 2013
Printed
Page 135
Do This box

Change the link to http://dogriffiths.github.io/HeadFirstC/

 Dawn Griffiths
Dawn Griffiths
 		 Dec 11, 2015 
139
Code snippet

The code is missing an fclose() for the "in" stream. Same error on pages 140, 143 and 145.

Note from the Author or Editor:
On pages 139, 140, 143, 145, add the following line of code immediately before the return 0;

fclose(in);

 Thomas Corbi?re  Aug 07, 2012  Jun 07, 2013
147
1st annotation

"If you run elvises.txt" should be changed to "If you run elvises.csv".

Note from the Author or Editor:
Correct. The top right annotation should refer to elvises.csv.

 Thomas Corbi?re  Aug 07, 2012  Jun 07, 2013
165-166
exercise code

Remove the semicolon at the end of "add_with_tax(float f);".

 Thomas Corbi?re  Aug 10, 2012  Jun 07, 2013
PDF
Page 167
"Data Type Sizes Close Up" code

The printf conversion character for sizeof on both int and float is incorrect.

"An int takes %z bytes\n" throws a warning (warning: unknown conversion type character 0x20 in format ), the conversion character(s) should be %zu.

It should read printf("An int takes %zu bytes\n", sizeof(int)); otherwise you get nothing for the bytes.

Note from the Author or Editor:
Both instances of %z should say %zu

 Michael Hans  Sep 06, 2012  Jun 07, 2013
182, 186
encrypt function

Remove the unused variable "char c".

Note from the Author or Editor:
Remove the char c; line of code from pages 182 and 186

 Thomas Corbi?re  Aug 10, 2012  Jun 07, 2013
186
3rd paragraph

"to the actual encrypt() function in encrypt.h" should be replaced by "to the actual encrypt() function in encrypt.c".

 Thomas Corbi?re  Aug 10, 2012  Jun 07, 2013
Printed
Page 215
Last line on the page

Change the link to http://dogriffiths.github.io/HeadFirstC/

 Dawn Griffiths
Dawn Griffiths
 		 Dec 11, 2015 
PDF
Page 218
First code sample

Inside the function label(...) there is a call to printf(). In this call, the "age" and "teeth" parameters are passed in reverse order from how they show up in the format string.

Note from the Author or Editor:
In the middle of the page, the final line of code inside void label(...) should say

name, species, age, teeth);

 B. Garvelink  May 06, 2012  Jun 07, 2013
220
3rd No Dumb Questions

"in the string" should be replaced by "in the struct".

 Thomas Corbi?re  Aug 10, 2012  Jun 07, 2013
249
3rd code snippet

".weight for the .amount" should be replaced by "".weight for the union".

Note from the Author or Editor:
Rephrase the annotation on the far right to:

Here, you're using a double designated identifier. It accesses the weight field of the .amount union.

 Thomas Corbi?re  Aug 09, 2012  Jun 07, 2013
269-270
Wording of "Sharpen your pencil"

" from one of piece of data" should be replaced by " from one piece of data".

 Thomas Corbi?re  Aug 09, 2012  Jun 07, 2013
PDF
Page 285
anywhere

Pages 285 and 286 introduce the strdup() function, but neglect to mention it's declared in string.h. GCC will complain about the implicit declaration and still compile a working executable, other compilers may not be so forgiving. The text should mention which header to include.

Note from the Author or Editor:
This is mentioned on page 285, first paragraph, last sentence. To make it clearer, change the font of string.h to courier new.

 Barend Garvelink  May 14, 2012  Jun 07, 2013
295-296
3rd description

"you could use to me" should be replaced by "you could use me".

Note from the Author or Editor:
3rd item under Description.

 Thomas Corbi?re  Aug 18, 2012  Jun 07, 2013
362
2nd make file rule annotation

"This creates the object from" should be replaced by "This creates the object file from".

 Thomas Corbi?re  Aug 18, 2012  Jun 07, 2013
PDF
Page 374
3rd paragraph

The point and purpose of the "Do this!" instruction regarding the -fPIC flag is nonobvious. Why should I "Do this!"? What am I looking for? The accompanying "Geek bits" blurb suggests it doesn't matter, just pass the compiler flag for portability.

Note from the Author or Editor:
Remove the "Do This!" from the page.

 Barend Garvelink  May 19, 2012  Jun 07, 2013
377
Using MinGW

"PATH="%PATH%:C:\libs"" should be replaced by "PATH="%PATH%;C:\libs"" as Windows is using semicolon to separate paths.

 Thomas Corbi?re  Aug 18, 2012  Jun 07, 2013
377
Using Cygwin

"If you?re compiled" should be replaced by "If you?ve compiled".

 Thomas Corbi?re  Aug 18, 2012  Jun 07, 2013
412
Wording of the exercise

All the code after the candidate code area should be removed because it will never be executed. either the exec() succeeds and the process is replaced or the exec() failed and the process will be stopped in the if statement.

Note from the Author or Editor:
On pages 412 and 414 remove the following lines of code after the rectangle area for the candidate code:

fprintf...
return1;
}
return 0;

 Thomas Corbi?re  Aug 17, 2012  Jun 07, 2013
432
Geek Bits

"&1 means ?to the Standard Input.?" should be replaced by "&1 means ?to the Standard Output.?"

Note from the Author or Editor:
This applies to the final annotation on the page.

 Thomas Corbi?re  Aug 17, 2012  Jun 07, 2013
453
3rd paragraph

"errno function" should be replaced by "errno variable".

Note from the Author or Editor:
Should say "...will also set the errno variable"

 Thomas Corbi?re  Aug 17, 2012  Jun 07, 2013
Printed
Page 454
United States

error handling function is diediedie(), but catch_signal() is called in main() with handle_interrupt, which does not exist.

Note from the Author or Editor:
Replace handle_interrupt throughout this page with diediedie

 Yitzchak Schaffer  Jul 10, 2012  Jun 07, 2013
455
2nd paragraph

"handle_interrupt()" should be replaced by "diediedie()".

 Thomas Corbi?re  Aug 17, 2012  Jun 07, 2013
461
Annotation of catch_signal()

"signal()" should be replaced by "catch_signal()".

 Thomas Corbi?re  Aug 17, 2012  Jun 07, 2013
479
bind_to_port() function

"htons(30000)" should be replaced by "htons(port)". Annotation about port 30000 could be removed too.

Note from the Author or Editor:
Replace htons(30000) with htons(port).

Remove annotation "name is Internet port 30000".

Change annotation "Grab port 30000" to "Grab port".

 Thomas Corbi?re  Aug 17, 2012  Jun 07, 2013
490
Code snippet in the terminal

"http/1.1" should be in capital letters "HTTP/1.1" according to RFC2616. This should also be corrected in the explanation of the GET command on the same page.

On the class attribute of the html element, add the missing equals sign.

Note from the Author or Editor:
Replace http/1.1 on this page with HTTP/1.1.

Replace class"client-nojs" with class="client-nojs".

 Thomas Corbi?re  Aug 17, 2012  Jun 07, 2013
493
Annotation for freeaddrinfo()

In "freeaddrinf0()", replace the number '0' with the letter 'o'.

 Thomas Corbi?re  Aug 17, 2012  Jun 07, 2013
Printed, PDF
Page 520
top left

Superimposed text due to incorrect text wrapping around "Blue Ribbon" image.

Andy Seronick  Jul 16, 2013  Jul 26, 2013
PDF
Page 527
third paragraph, "Events"

"fires her canyon" should be "fires her cannon"

 David Demko  Jun 14, 2013 
ePub
Page 2780
2nd zoomable screenshot

Kindle version, loc 2780, the Case of the Magic Bullet. Second zoomable screenshot should say 'Masked raider is DEAD!, Jimmy is DEAD!'

Note from the Author or Editor:
Kindle version should reflect printed version (page 77)

 Peter Gustafson  Sep 03, 2012  Jun 07, 2013