ark@alice.UUCP (07/19/88)
I received mail today from Jonathan Bressel suggesting that it would be useful to give more detailed information about ``C Traps and Pitfalls.'' Excellent idea. Here it is: ABSTRACT Even C experts come across problems that require days of debugging to fix. This book helps prevent such problems by showing how C programmers get themselves into trouble. Each of the book's many examples has trapped a professional C programmer. Distilled from the author's experience over a decade of programming in C, the book also includes advice for mastering often misunderstood parts of C. TABLE OF CONTENTS 0 Introduction 1 Lexical pitfalls 1.1 = is not == 1.2 & and | are not && or || 1.3 Greedy lexical analysis 1.4 Integer constants 1.5 Strings and characters 2 Syntactic pitfalls 2.1 Understanding function declarations 2.2 Operators don't always have the precedence you want 2.3 Watch those semicolons! 2.4 The switch statement 2.5 Calling functions 2.6 The dangling else problem 3 Semantic pitfalls 3.1 Pointers and arrays 3.2 Pointers are not arrays 3.3 Array declarations as parameters 3.4 Eschew synecdoche 3.5 Null pointers are not null strings 3.6 Counting and asymmetric bounds 3.7 Order of evaluation 3.8 The &&, ||, and ! operators 3.9 Integer overflow 3.10 Returning a value from main 4 Linkage 4.1 What is a linker? 4.2 Declarations vs. definitions 4.3 Name conflicts and the static modifier 4.4 Arguments, parameters, and return values 4.5 Checking external types 4.6 Header files 5 Library functions 5.1 getchar returns an integer 5.2 Updating a sequential file 5.3 Buffered output and memory allocation 5.4 Using errno for error detection 5.5 The signal function 6 The preprocessor 6.1 Spaces matter in macro definitions 6.2 Macros are not functions 6.3 Macros are not statements 6.4 Macros are not type definitions 7 Portability pitfalls 7.1 Coping with change 7.2 What's in a name? 7.3 How big is an integer? 7.4 Are characters signed or unsigned? 7.5 Shift operators 7.6 Memory location zero 7.7 How does division truncate? 7.8 How big is a random number? 7.9 Case conversion 7.10 Free first, then reallocate? 7.11 An example of portability problems 8 Advice and answers 8.1 Advice 8.2 Answers Appendix: printf, varargs, and stdarg A.1 The printf family Simple format types Modifiers Flags Variable field width and precision Neologisms Anachronisms A.2 Variable argument lists with varargs.h Implementing varargs.h A.3 stdarg.h: the ANSI varargs.h