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21st Century C

Cover of 21st Century C by Ben Klemens Published by O'Reilly Media, Inc.
  1. 21st Century C
  2. SPECIAL OFFER: Upgrade this ebook with O’Reilly
  3. A Note Regarding Supplemental Files
  4. Preface
    1. C Is Punk Rock
    2. Q & A (Or, the Parameters of the Book)
    3. Standards: So Many to Choose From
      1. The POSIX Standard
    4. Some Logistics
      1. Conventions Used in This Book
      2. Using Code Examples
      3. Safari® Books Online
      4. How to Contact Us
      5. Acknowledgments
  5. I. The Environment
    1. 1. Set Yourself Up for Easy Compilation
      1. Use a Package Manager
      2. Compiling C with Windows
      3. Which Way to the Library?
      4. Using Makefiles
      5. Using Libraries from Source
      6. Using Libraries from Source (Even if Your Sysadmin Doesn’t Want You To)
      7. Compiling C Programs via Here Document
    2. 2. Debug, Test, Document
      1. Using a Debugger
      2. Using Valgrind to Check for Errors
      3. Unit Testing
      4. Interweaving Documentation
      5. Error Checking
    3. 3. Packaging Your Project
      1. The Shell
      2. Makefiles vs. Shell Scripts
      3. Packaging Your Code with Autotools
    4. 4. Version Control
      1. Changes via diff
      2. Git’s Objects
      3. Trees and Their Branches
      4. Remote Repositories
    5. 5. Playing Nice with Others
      1. The Process
      2. Python Host
  6. II. The Language
    1. 6. Your Pal the Pointer
      1. Automatic, Static, and Manual Memory
      2. Persistent State Variables
      3. Pointers Without malloc
    2. 7. C Syntax You Can Ignore
      1. Don’t Bother Explicitly Returning from main
      2. Let Declarations Flow
      3. Cast Less
      4. Enums and Strings
      5. Labels, gotos, switches, and breaks
      6. Deprecate Float
    3. 8. Obstacles and Opportunity
      1. Cultivate Robust and Flourishing Macros
      2. Linkage with static and extern
      3. The const Keyword
    4. 9. Text
      1. Making String Handling Less Painful with asprintf
      2. A Pæan to strtok
      3. Unicode
    5. 10. Better Structures
      1. Compound Literals
      2. Variadic Macros
      3. Safely Terminated Lists
      4. Foreach
      5. Vectorize a Function
      6. Designated Initializers
      7. Initialize Arrays and Structs with Zeros
      8. Typedefs Save the Day
      9. Return Multiple Items from a Function
      10. Flexible Function Inputs
      11. The Void Pointer and the Structures It Points To
    6. 11. Object-Oriented Programming in C
      1. What You Don’t Get (and Why You Won’t Miss It)
      2. Extending Structures and Dictionaries
      3. Functions in Your Structs
      4. Count References
    7. 12. Libraries
      1. GLib
      2. POSIX
      3. The GNU Scientific Library
      4. SQLite
      5. libxml and cURL
  7. Epilogue
  8. Glossary
  9. Bibliography
  10. Index
  11. About the Author
  12. Colophon
  13. SPECIAL OFFER: Upgrade this ebook with O’Reilly
  14. Copyright
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Chapter 9. Text

I believe that in the end the word will break cement.

Pussy Riot, paraphrasing Aleksandr Solzhenitsyn in a statement on 8 August 2012.

A string of letters is an array of indeterminate length, and automatically allocated arrays (allocated on the stack) can’t be resized, and that in a nutshell is the problem with text in C. Fortunately, many others before us have already faced this problem and produced at least partial solutions. A handful of C-standard and POSIX-standard functions are sufficient to handle many of our string-building needs.

Also, C was designed in the 1970s, before the invention of non-English languages. Again, with the right functions (and the right understanding of how language is encoded), C's original focus on English is not a real problem.

Making String Handling Less Painful with asprintf

The asprintf function allocates the amount of string space you will need, and then fills the string. That means you never really have to worry about string-allocing again.

asprintf is not part of the C standard, but it’s available on systems with the GNU or BSD standard library, which covers pretty much everybody. Further, the GNU libiberty library provides a version of asprintf that you can cut and paste into your own code base; see the next section.

The old way made people homicidal (or suicidal, depending on temperament), because they first had to get the length of the string they were about to fill, allocate space, and then actually write to the space. Don’t forget ...

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