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466
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1 <chapter>
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2 <title>The C Compiler System</title>
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3
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4 <section>
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5 <title>Introduction</title>
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6 <para>
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468
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7 The "C" programming language is rapidly growing in popularity
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8 and seems destined to become one of the most popular programming
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9 languages used for microcomputers. The rapid rise in the use of C
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10 is not surprising. C is an incredibly versatile and efficient
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11 language that can handle tasks that previously would have required
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12 complex assembly language programming.
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466
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13 </para>
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14
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15 </section>
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16 <section>
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468
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17 <title>The Language Implementation</title>
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466
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18 <para>
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468
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19 OS-9 C is implemented almost exactly as described in 'The C
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20 Programming Language' by Kernighan and Ritchie (hereafter referred
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21 to as K&R).
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22 </para>
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23 <para>
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24 Allthough this version of C follows the specification faithfully,
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25 there are some differences. The differences mostly reflect
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26 parts of C that are obsolete or the constraints imposed by memory
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27 size limitations.
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466
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28 </para>
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472
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29
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30 </section>
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31 <section>
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32 <title>Compiler Option Flags</title>
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33 <para>
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34 The compiler recognizes several command-line option flags which
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35 modify the compilation process where needed. All flags are
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36 recognized before compilation commences so the flags may be placed
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37 anywhere on the command line. Flags may be ran together as in "-ro",
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38 except where a flag is followed by something else; see "-f=" and
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39 "-d" for examples.
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40 </para>
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41 <para>
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42 -A
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43 suppresses assembly, leaving the output as assembler code in a
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44 file whose name is postfixed ".a".
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45 </para>
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46 <para>
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47 -E=<number>
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48 Set the edition number constant byte to the number given. This is
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49 an OS-9 convention for memory modules.
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50 </para>
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51 <para>
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52 -O
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53 inhibits the assembly code optimizer pass. The optimizer will
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54 shorten object code by about 11% with a comparable increase in speed
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55 and is recommended for production versions of de-bugged programs.
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56 </para>
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57 <para>
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58 -P
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59 invokes the profiler to generate function frequency
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60 statistics after program execution.
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61 </para>
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62 <para>
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63 -R
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64 suppresses linking library modules into an executable program.
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65 Outputs are left in files with postfixes ".r".
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66 </para>
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67 <para>
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68 -M=<memory size>
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69 will instruct the linker to allocate <memory size>
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70 for data, stack, and parameter area. Memory size may be expressed
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71 in pages (an integer) or in kilobytes by appending "k" to an
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72 integer. For more details of the use of this option, see the
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73 "Memory Management" section of this manual.
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74 </para>
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75 <para>
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76 -L=<filename>
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77 specifies a library to be searched by the linker
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78 before the Standard Library and system interface.
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79 </para>
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80 <para>
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81 -F=<path>
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82 overrides the above output file naming. The output file
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83 will be left with <filename> as its name. This flag does not make
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84 sense in multiple source mode, and either the -a or -r flag is also
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85 present. The module will be called the last name in <path>.
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86 </para>
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87 <para>
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88 -C
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89 will output the source code as comments with the assembler code.
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90 </para>
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91 <para>
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92 -S
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93 stops the generation of stack-checking code. -S should only be
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94 used with great care when the appication is extremely time-critical
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95 and when the use of the stack by compiler generated code is fully
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96 understood.
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97 </para>
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98 <para>
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99 -D<identifier>
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100 is equivalent to "#define <identifier>" written in
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101 the source file. -D is useful where different versions of a program
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102 are maintained in one source file and differentiated by means of the
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103 "#ifdef" of "#ifndef" pre-processor directives. If the <identifier>
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104 is used as a macro for expansion by the pre-processor, "1"(one) will
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105 be the expanded "value" unless the form "-d<identifier>=<string>" is
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106 used in which case the expansion will be <string>.
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107 </para>
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108 <table frame="none">
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109 <title>Command Line and Option Flag Examples</title>
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110 <tgroup cols="3">
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111 <colspec colwidth="1.5in" colname="c1">
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112 <colspec colwidth="1.5in" colname="c2">
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113 <colspec colwidth="1.5in" colname="c3">
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114 <thead>
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115 <row>
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116 <entry>command line</entry>
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117 <entry>action</entry>
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118 <entry>output file(s)</entry>
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119 </row>
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120 </thead>
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121 <tbody>
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122 <row>
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123 <entry>cc prg.c</entry>
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124 <entry>compile to an executable program</entry>
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125 <entry>prg</entry>
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126 <entry></entry>
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127 </row>
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128 <row>
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129 <entry>cc prg.c -a</entry>
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130 <entry>compile to assembly language source code</entry>
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131 <entry>prg.a</entry>
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132 </row>
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133 <row>
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134 <entry>cc prg.c -r</entry>
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135 <entry>compile to relocatable module</entry>
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136 <entry>prg.r</entry>
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137 </row>
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138 <row>
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139 <entry>cc prg1.c prg2.c prg3.c</entry>
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140 <entry>compile to executable program</entry>
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141 <entry>prg1.r, prg2.r, prg3.r, output</entry>
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142 </row>
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143 <row>
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144 <entry>cc prg1.c prg2.a prg3.r</entry>
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145 <entry>compile prg1.c, assemble prg2.a and combine all into
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146 and executable program</entry>
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147 <entry>prg1.r, prg2.r</entry>
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148 </row>
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149 <row>
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150 <entry>cc prg1.c prg2.c -a</entry>
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151 <entry>compile to assembly language source code</entry>
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152 <entry>prg1.a, prg2.a</entry>
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153 </row>
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154 <row>
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155 <entry>cc prg1.c prg2.c -f=prg</entry>
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156 <entry>compile to executable program</entry>
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157 <entry>prg</entry>
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158 </row>
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159 </tbody>
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160 </tgroup>
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161 </table>
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162
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466
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163 </section>
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164 </chapter>
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