Fundamentals of System Programming Keio University’s Shonan Fujisawa Campus Spring 2015 3 Fundamentals of System Programming original by Hiroyuki Kusumoto adapted by Rodney Van Meter October 2, 2015 Contents Course Introduction iii 0.1 TotheIndependentReader . v 0.2 GoalsandStructureoftheClass . v 0.3 LearningOutcomes........................... vi 0.4 TotheInstructor ............................viii 0.5 This Class in the Keio Shonan Fujisawa Campus Curriculum . viii 0.6 WhyC?................................. x 0.7 WhyaNewBook? ........................... xi 0.8 HowtoReadthisBook ........................ xi 0.9 AdditionalRecommendedBooks . xii I Core Concepts and the C Programming Language in a UNIX Environment 1 1 The Traditional “Hello, World!” 3 1.1 Concepts ................................ 3 1.2 JavaandC ............................... 3 1.2.1 Object-oriented languages and procedural languages .... 3 1.2.2 InterpreterandCompiler . 4 1.2.3 Similarities ........................... 7 1.2.4 AFewDifferences ....................... 7 1.3 Clanguagebriefsummary. 8 1.3.1 OverallStructureofaProgram . 8 1.3.2 CompileandExecution . 8 1.3.3 Comments............................ 9 1.3.4 VariableandType . 10 1.3.5 Function............................. 12 1.3.6 FunctionandTypes . 14 1.3.7 AutomaticTypeConversion. 18 i ii CONTENTS 1.3.8 Statement............................ 19 1.3.9 Expression ........................... 22 1.3.10 Library ............................. 23 1.3.11 StandardInput/OutputLibrary . 24 1.4 Tools................................... 25 1.4.1 Gcc ............................... 25 1.4.2 Make .............................. 25 1.4.3 man(theUnixmanual) . 26 1.4.4 OtherUNIXutilitiesandcommands . 26 1.5 Exercises ................................ 26 2 Fundamental Data Types 29 2.1 Concepts ................................ 29 2.2 IntegerDataTypes........................... 29 2.3 FloatingPointNumberDataTypes . 33 2.4 Mixed arithmetic operation for an integer and a floating point number 34 2.5 Manipulating bitfields and bits within numbers . 34 2.6 Tools................................... 35 2.6.1 MoreonMake ......................... 35 2.7 Exercises ................................ 35 3 Arrays, Structs and Pointers 37 3.1 Concepts ................................ 37 3.2 Arrays.................................. 37 3.3 Pointers ................................. 41 3.3.1 Pointerexplanationandvalue. 42 3.3.2 Characterarraysandpointers. 44 3.3.3 Pointervariables . 47 3.3.4 Manipulationofpointervariables . 50 3.4 PointersandFunctions. 53 3.4.1 Functioncallsandarguments . 53 3.4.2 Howtopassarrays. 56 3.5 Structures................................ 59 3.6 Tools................................... 62 3.6.1 gcc: phasesofcompilation. 62 3.6.2 git ................................ 62 3.7 Exercises ................................ 62 CONTENTS iii 4 String Processing and Pointers 65 4.1 Concepts ................................ 65 4.2 Stringsasarrays ............................ 66 4.2.1 Copyingandconcatenatingstrings . 69 4.2.2 Comparisonofstrings . 72 4.2.3 Classifyingcharacters . 74 4.2.4 Stringsandnumericaldata . 76 4.3 Dealingwithnon-ASCIIcharacters . 80 4.4 Structuresandfunctions. 82 4.5 Tools................................... 86 4.5.1 ThePreprocessor. 86 4.6 Exercises ................................ 89 5 Memory Management, Scope in Naming, and More Control 91 5.1 Concepts ................................ 91 5.1.1 Memorymanagement . 91 5.1.2 Scope .............................. 92 5.2 Dynamicmemoryusewithpointers. 92 5.3 Scopeofvariables............................ 95 5.4 Controlstructures ........................... 99 5.4.1 switch ............................. 99 5.4.2 break ..............................102 5.4.3 continue statement ......................104 5.5 Tools...................................105 5.5.1 Interpretinggcc’serrormessages . .105 5.6 Exercises ................................106 6 Input/Output 111 6.1 Concepts ................................111 6.1.1 FilesandI/O..........................111 6.1.2 Commandlinearguments . .113 6.1.3 Environmentvariables . .114 6.2 StandardInput/Ouput. .114 6.3 Streaminputandoutput . .116 6.3.1 fopen()/fprintf()/fgets()/fclose() . 116 6.3.2 Handlingerrorsfromlibrarycalls. .118 6.3.3 Skippingaroundinafile. .121 6.4 Inputandoutputusingfiledescriptors . 121 6.4.1 open()/write()/read()/close() . 121 6.4.2 Handlingerrorsfromsystemcalls. .124 6.4.3 Skippingaroundinafile. .125 iv CONTENTS 6.5 mmap() .................................126 6.6 Makingfilenamesfromstrings . .126 6.7 Commandlinearguments . .127 6.7.1 Commandlineoptions . .129 6.8 Environmentvariables . .129 6.9 Tools...................................130 6.9.1 Make: building programs from more than one file . 130 6.10Exercises ................................133 First Interlude 137 7 Linked Lists and Recursion 139 7.1 Concepts ................................139 7.1.1 Linkedlists ...........................139 7.1.2 Recursion ............................140 7.2 Self-referentialstructures . 140 7.3 2-DArrays ...............................142 7.4 Recursion ................................142 7.5 Tools...................................143 7.5.1 GeneratingDependenciesinMake . 143 7.6 Exercises ................................143 8 Algorithms, Intermediate Data Structures, and Analysis 149 8.1 Concepts ................................149 8.1.1 Big-O notation: How long will my computation take? . 149 8.1.2 Sorting .............................151 8.1.3 BasicDataStructures . .151 8.1.4 BasicBinarySearchTrees . .153 8.1.5 Red-BlackBinaryTrees . .153 8.2 C.....................................156 8.3 Tools...................................156 8.3.1 gprof: profilingexecution . .156 8.4 Exercises ................................157 9 Finite State Machines 159 9.1 Concepts ................................159 9.2 C.....................................159 9.3 Tools...................................159 9.4 Exercises ................................159 CONTENTS v 10WritingandTestingSystemUtilities 161 10.1Concepts ................................161 10.2C.....................................162 10.3Tools...................................162 10.4Exercises ................................164 Second Interlude 165 II Achieving Scale in the Real World: Concurrency, Parallelism, Communication and 167 11 Soft Real-Time Computing 169 11.1Concepts ................................169 11.2C.....................................169 11.2.1 AnArduinomultitasker . .169 11.3Tools...................................172 11.4Exercises ................................172 12 Processes and Pipelines of Programs 173 12.1Concepts ................................173 12.2C.....................................173 12.3Tools...................................173 12.4Exercises ................................173 13Signals: CommunicatingAsynchronously 175 13.1Concepts ................................175 13.2C.....................................175 13.3Tools...................................175 13.4Exercises ................................175 14Threads:AbstractingProcessors 177 14.1Concepts ................................177 14.2C.....................................177 14.3Tools...................................177 14.4Exercises ................................177 15 Parallelism: OpenMP 179 15.1Concepts ................................179 15.2C.....................................179 15.3Tools...................................179 15.4Exercises ................................179 vi CONTENTS Third Interlude 181 16Communication:IPNetworkingBasics 183 16.1Concepts ................................183 16.2C.....................................183 16.3Tools...................................183 16.4Exercises ................................183 17Naming:theDomainNameService 185 17.1Concepts ................................185 17.2C.....................................185 17.3Tools...................................185 17.4Exercises ................................185 18 Communication: TCP Sockets 1 187 18.1Concepts ................................187 18.2C.....................................187 18.3Tools...................................187 18.4Exercises ................................187 19 Distribution: TCP Sockets 2 189 19.1Concepts ................................189 19.2Tools...................................189 19.3Exercises ................................189 A C Syntax Supplement 191 A.1 StorageClass ..............................191 A.1.1 volatile .............................197 A.1.2 const...............................198 A.2 Unions..................................199 A.3 Macros..................................199 A.3.1 Object-likemacros . .199 A.3.2 Function-likemacros . .200 A.3.3 Thetrapofmacros. .200 A.4 ConditionalCompilation. .201 A.4.1 Usingmacros ..........................201 A.4.2 Platformdependentcompilation . 204 A.5 Operators ................................205 A.5.1 Operatorprecedence . .205 A.5.2 Conditional operator for expressions . 205 A.5.3 =operator ...........................206 A.5.4 Incrementanddecrementoperators . 207 CONTENTS i A.5.5 Comma(,)operator . .208 A.6 FinePointsofExecutionOrder . .209 A.6.1 Undefinedbehavior. .209 A.6.2 Logicalexpressions . .210 A.7 FunctionPointers. .211 A.7.1 Example: the qsort libraryfunction . .211 A.7.2 Arrayofpointerstofunctions . .212 B Development Environment Addendum: MacOS 215 B.1 LLVM ..................................215 B.2 Clang ..................................215 B.3 LLDB ..................................215