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1 @c Copyright (c) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
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2 @c Free Software Foundation, Inc.
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3 @c This is part of the CPP and GCC manuals.
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4 @c For copying conditions, see the file gcc.texi.
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5
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6 @c ---------------------------------------------------------------------
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7 @c Options affecting the preprocessor
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8 @c ---------------------------------------------------------------------
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9
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10 @c If this file is included with the flag ``cppmanual'' set, it is
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11 @c formatted for inclusion in the CPP manual; otherwise the main GCC manual.
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12
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13 @table @gcctabopt
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14 @item -D @var{name}
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15 @opindex D
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16 Predefine @var{name} as a macro, with definition @code{1}.
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17
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18 @item -D @var{name}=@var{definition}
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19 The contents of @var{definition} are tokenized and processed as if
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20 they appeared during translation phase three in a @samp{#define}
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21 directive. In particular, the definition will be truncated by
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22 embedded newline characters.
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23
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24 If you are invoking the preprocessor from a shell or shell-like
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25 program you may need to use the shell's quoting syntax to protect
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26 characters such as spaces that have a meaning in the shell syntax.
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27
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28 If you wish to define a function-like macro on the command line, write
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29 its argument list with surrounding parentheses before the equals sign
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30 (if any). Parentheses are meaningful to most shells, so you will need
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31 to quote the option. With @command{sh} and @command{csh},
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32 @option{-D'@var{name}(@var{args@dots{}})=@var{definition}'} works.
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33
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34 @option{-D} and @option{-U} options are processed in the order they
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35 are given on the command line. All @option{-imacros @var{file}} and
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36 @option{-include @var{file}} options are processed after all
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37 @option{-D} and @option{-U} options.
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38
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39 @item -U @var{name}
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40 @opindex U
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41 Cancel any previous definition of @var{name}, either built in or
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42 provided with a @option{-D} option.
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43
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44 @item -undef
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45 @opindex undef
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46 Do not predefine any system-specific or GCC-specific macros. The
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47 standard predefined macros remain defined.
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48 @ifset cppmanual
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49 @xref{Standard Predefined Macros}.
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50 @end ifset
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51
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52 @item -I @var{dir}
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53 @opindex I
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54 Add the directory @var{dir} to the list of directories to be searched
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55 for header files.
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56 @ifset cppmanual
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57 @xref{Search Path}.
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58 @end ifset
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59 Directories named by @option{-I} are searched before the standard
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60 system include directories. If the directory @var{dir} is a standard
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61 system include directory, the option is ignored to ensure that the
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62 default search order for system directories and the special treatment
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63 of system headers are not defeated
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64 @ifset cppmanual
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65 (@pxref{System Headers})
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66 @end ifset
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67 .
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68 If @var{dir} begins with @code{=}, then the @code{=} will be replaced
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69 by the sysroot prefix; see @option{--sysroot} and @option{-isysroot}.
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70
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71 @item -o @var{file}
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72 @opindex o
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73 Write output to @var{file}. This is the same as specifying @var{file}
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74 as the second non-option argument to @command{cpp}. @command{gcc} has a
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75 different interpretation of a second non-option argument, so you must
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76 use @option{-o} to specify the output file.
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77
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78 @item -Wall
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79 @opindex Wall
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80 Turns on all optional warnings which are desirable for normal code.
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81 At present this is @option{-Wcomment}, @option{-Wtrigraphs},
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82 @option{-Wmultichar} and a warning about integer promotion causing a
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83 change of sign in @code{#if} expressions. Note that many of the
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84 preprocessor's warnings are on by default and have no options to
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85 control them.
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86
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87 @item -Wcomment
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88 @itemx -Wcomments
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89 @opindex Wcomment
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90 @opindex Wcomments
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91 Warn whenever a comment-start sequence @samp{/*} appears in a @samp{/*}
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92 comment, or whenever a backslash-newline appears in a @samp{//} comment.
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93 (Both forms have the same effect.)
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94
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95 @item -Wtrigraphs
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96 @opindex Wtrigraphs
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97 @anchor{Wtrigraphs}
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98 Most trigraphs in comments cannot affect the meaning of the program.
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99 However, a trigraph that would form an escaped newline (@samp{??/} at
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100 the end of a line) can, by changing where the comment begins or ends.
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101 Therefore, only trigraphs that would form escaped newlines produce
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102 warnings inside a comment.
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103
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104 This option is implied by @option{-Wall}. If @option{-Wall} is not
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105 given, this option is still enabled unless trigraphs are enabled. To
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106 get trigraph conversion without warnings, but get the other
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107 @option{-Wall} warnings, use @samp{-trigraphs -Wall -Wno-trigraphs}.
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108
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109 @item -Wtraditional
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110 @opindex Wtraditional
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111 Warn about certain constructs that behave differently in traditional and
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112 ISO C@. Also warn about ISO C constructs that have no traditional C
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113 equivalent, and problematic constructs which should be avoided.
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114 @ifset cppmanual
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115 @xref{Traditional Mode}.
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116 @end ifset
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117
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118 @item -Wundef
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119 @opindex Wundef
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120 Warn whenever an identifier which is not a macro is encountered in an
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121 @samp{#if} directive, outside of @samp{defined}. Such identifiers are
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122 replaced with zero.
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123
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124 @item -Wunused-macros
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125 @opindex Wunused-macros
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126 Warn about macros defined in the main file that are unused. A macro
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127 is @dfn{used} if it is expanded or tested for existence at least once.
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128 The preprocessor will also warn if the macro has not been used at the
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129 time it is redefined or undefined.
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130
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131 Built-in macros, macros defined on the command line, and macros
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132 defined in include files are not warned about.
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133
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134 @emph{Note:} If a macro is actually used, but only used in skipped
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135 conditional blocks, then CPP will report it as unused. To avoid the
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136 warning in such a case, you might improve the scope of the macro's
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137 definition by, for example, moving it into the first skipped block.
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138 Alternatively, you could provide a dummy use with something like:
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139
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140 @smallexample
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141 #if defined the_macro_causing_the_warning
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142 #endif
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143 @end smallexample
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144
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145 @item -Wendif-labels
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146 @opindex Wendif-labels
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147 Warn whenever an @samp{#else} or an @samp{#endif} are followed by text.
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148 This usually happens in code of the form
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149
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150 @smallexample
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151 #if FOO
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152 @dots{}
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153 #else FOO
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154 @dots{}
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155 #endif FOO
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156 @end smallexample
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157
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158 @noindent
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159 The second and third @code{FOO} should be in comments, but often are not
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160 in older programs. This warning is on by default.
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161
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162 @item -Werror
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163 @opindex Werror
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164 Make all warnings into hard errors. Source code which triggers warnings
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165 will be rejected.
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166
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167 @item -Wsystem-headers
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168 @opindex Wsystem-headers
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169 Issue warnings for code in system headers. These are normally unhelpful
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170 in finding bugs in your own code, therefore suppressed. If you are
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171 responsible for the system library, you may want to see them.
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172
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173 @item -w
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174 @opindex w
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175 Suppress all warnings, including those which GNU CPP issues by default.
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176
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177 @item -pedantic
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178 @opindex pedantic
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179 Issue all the mandatory diagnostics listed in the C standard. Some of
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180 them are left out by default, since they trigger frequently on harmless
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181 code.
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182
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183 @item -pedantic-errors
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184 @opindex pedantic-errors
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185 Issue all the mandatory diagnostics, and make all mandatory diagnostics
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186 into errors. This includes mandatory diagnostics that GCC issues
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187 without @samp{-pedantic} but treats as warnings.
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188
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189 @item -M
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190 @opindex M
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191 @cindex make
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192 @cindex dependencies, make
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193 Instead of outputting the result of preprocessing, output a rule
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194 suitable for @command{make} describing the dependencies of the main
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195 source file. The preprocessor outputs one @command{make} rule containing
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196 the object file name for that source file, a colon, and the names of all
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197 the included files, including those coming from @option{-include} or
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198 @option{-imacros} command line options.
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199
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200 Unless specified explicitly (with @option{-MT} or @option{-MQ}), the
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201 object file name consists of the name of the source file with any
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202 suffix replaced with object file suffix and with any leading directory
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203 parts removed. If there are many included files then the rule is
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204 split into several lines using @samp{\}-newline. The rule has no
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205 commands.
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206
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207 This option does not suppress the preprocessor's debug output, such as
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208 @option{-dM}. To avoid mixing such debug output with the dependency
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209 rules you should explicitly specify the dependency output file with
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210 @option{-MF}, or use an environment variable like
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211 @env{DEPENDENCIES_OUTPUT} (@pxref{Environment Variables}). Debug output
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212 will still be sent to the regular output stream as normal.
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213
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214 Passing @option{-M} to the driver implies @option{-E}, and suppresses
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215 warnings with an implicit @option{-w}.
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216
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217 @item -MM
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218 @opindex MM
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219 Like @option{-M} but do not mention header files that are found in
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220 system header directories, nor header files that are included,
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221 directly or indirectly, from such a header.
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222
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223 This implies that the choice of angle brackets or double quotes in an
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224 @samp{#include} directive does not in itself determine whether that
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225 header will appear in @option{-MM} dependency output. This is a
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226 slight change in semantics from GCC versions 3.0 and earlier.
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227
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228 @anchor{dashMF}
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229 @item -MF @var{file}
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230 @opindex MF
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231 When used with @option{-M} or @option{-MM}, specifies a
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232 file to write the dependencies to. If no @option{-MF} switch is given
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233 the preprocessor sends the rules to the same place it would have sent
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234 preprocessed output.
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235
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236 When used with the driver options @option{-MD} or @option{-MMD},
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237 @option{-MF} overrides the default dependency output file.
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238
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239 @item -MG
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240 @opindex MG
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241 In conjunction with an option such as @option{-M} requesting
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242 dependency generation, @option{-MG} assumes missing header files are
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243 generated files and adds them to the dependency list without raising
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244 an error. The dependency filename is taken directly from the
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245 @code{#include} directive without prepending any path. @option{-MG}
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246 also suppresses preprocessed output, as a missing header file renders
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247 this useless.
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248
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249 This feature is used in automatic updating of makefiles.
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250
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251 @item -MP
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252 @opindex MP
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253 This option instructs CPP to add a phony target for each dependency
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254 other than the main file, causing each to depend on nothing. These
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255 dummy rules work around errors @command{make} gives if you remove header
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256 files without updating the @file{Makefile} to match.
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257
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258 This is typical output:
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259
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260 @smallexample
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261 test.o: test.c test.h
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262
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263 test.h:
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264 @end smallexample
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265
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266 @item -MT @var{target}
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267 @opindex MT
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268
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269 Change the target of the rule emitted by dependency generation. By
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270 default CPP takes the name of the main input file, deletes any
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271 directory components and any file suffix such as @samp{.c}, and
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272 appends the platform's usual object suffix. The result is the target.
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273
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274 An @option{-MT} option will set the target to be exactly the string you
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275 specify. If you want multiple targets, you can specify them as a single
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276 argument to @option{-MT}, or use multiple @option{-MT} options.
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277
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278 For example, @option{@w{-MT '$(objpfx)foo.o'}} might give
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279
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280 @smallexample
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281 $(objpfx)foo.o: foo.c
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282 @end smallexample
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283
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284 @item -MQ @var{target}
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285 @opindex MQ
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286
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287 Same as @option{-MT}, but it quotes any characters which are special to
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288 Make. @option{@w{-MQ '$(objpfx)foo.o'}} gives
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289
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290 @smallexample
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291 $$(objpfx)foo.o: foo.c
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292 @end smallexample
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293
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294 The default target is automatically quoted, as if it were given with
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295 @option{-MQ}.
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296
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297 @item -MD
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298 @opindex MD
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299 @option{-MD} is equivalent to @option{-M -MF @var{file}}, except that
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300 @option{-E} is not implied. The driver determines @var{file} based on
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301 whether an @option{-o} option is given. If it is, the driver uses its
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302 argument but with a suffix of @file{.d}, otherwise it takes the name
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303 of the input file, removes any directory components and suffix, and
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304 applies a @file{.d} suffix.
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305
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306 If @option{-MD} is used in conjunction with @option{-E}, any
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307 @option{-o} switch is understood to specify the dependency output file
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308 (@pxref{dashMF,,-MF}), but if used without @option{-E}, each @option{-o}
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309 is understood to specify a target object file.
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310
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311 Since @option{-E} is not implied, @option{-MD} can be used to generate
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312 a dependency output file as a side-effect of the compilation process.
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313
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314 @item -MMD
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315 @opindex MMD
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316 Like @option{-MD} except mention only user header files, not system
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317 header files.
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318
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319 @ifclear cppmanual
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320 @item -fpch-deps
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321 @opindex fpch-deps
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322 When using precompiled headers (@pxref{Precompiled Headers}), this flag
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323 will cause the dependency-output flags to also list the files from the
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324 precompiled header's dependencies. If not specified only the
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325 precompiled header would be listed and not the files that were used to
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326 create it because those files are not consulted when a precompiled
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327 header is used.
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328
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329 @item -fpch-preprocess
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330 @opindex fpch-preprocess
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331 This option allows use of a precompiled header (@pxref{Precompiled
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332 Headers}) together with @option{-E}. It inserts a special @code{#pragma},
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333 @code{#pragma GCC pch_preprocess "<filename>"} in the output to mark
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334 the place where the precompiled header was found, and its filename. When
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335 @option{-fpreprocessed} is in use, GCC recognizes this @code{#pragma} and
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336 loads the PCH@.
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337
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338 This option is off by default, because the resulting preprocessed output
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339 is only really suitable as input to GCC@. It is switched on by
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340 @option{-save-temps}.
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341
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342 You should not write this @code{#pragma} in your own code, but it is
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343 safe to edit the filename if the PCH file is available in a different
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344 location. The filename may be absolute or it may be relative to GCC's
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345 current directory.
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346
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347 @end ifclear
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348 @item -x c
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349 @itemx -x c++
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350 @itemx -x objective-c
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351 @itemx -x assembler-with-cpp
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352 @opindex x
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353 Specify the source language: C, C++, Objective-C, or assembly. This has
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354 nothing to do with standards conformance or extensions; it merely
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355 selects which base syntax to expect. If you give none of these options,
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356 cpp will deduce the language from the extension of the source file:
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357 @samp{.c}, @samp{.cc}, @samp{.m}, or @samp{.S}. Some other common
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358 extensions for C++ and assembly are also recognized. If cpp does not
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359 recognize the extension, it will treat the file as C; this is the most
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360 generic mode.
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361
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362 @emph{Note:} Previous versions of cpp accepted a @option{-lang} option
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363 which selected both the language and the standards conformance level.
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364 This option has been removed, because it conflicts with the @option{-l}
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365 option.
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366
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367 @item -std=@var{standard}
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368 @itemx -ansi
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369 @opindex ansi
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370 @opindex std=
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371 Specify the standard to which the code should conform. Currently CPP
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372 knows about C and C++ standards; others may be added in the future.
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373
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374 @var{standard}
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375 may be one of:
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376 @table @code
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377 @item iso9899:1990
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378 @itemx c89
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379 The ISO C standard from 1990. @samp{c89} is the customary shorthand for
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380 this version of the standard.
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381
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382 The @option{-ansi} option is equivalent to @option{-std=c89}.
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383
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384 @item iso9899:199409
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385 The 1990 C standard, as amended in 1994.
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386
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387 @item iso9899:1999
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388 @itemx c99
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389 @itemx iso9899:199x
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390 @itemx c9x
|
|
|
391 The revised ISO C standard, published in December 1999. Before
|
|
|
392 publication, this was known as C9X@.
|
|
|
393
|
|
|
394 @item gnu89
|
|
|
395 The 1990 C standard plus GNU extensions. This is the default.
|
|
|
396
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|
|
397 @item gnu99
|
|
|
398 @itemx gnu9x
|
|
|
399 The 1999 C standard plus GNU extensions.
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|
|
400
|
|
|
401 @item c++98
|
|
|
402 The 1998 ISO C++ standard plus amendments.
|
|
|
403
|
|
|
404 @item gnu++98
|
|
|
405 The same as @option{-std=c++98} plus GNU extensions. This is the
|
|
|
406 default for C++ code.
|
|
|
407 @end table
|
|
|
408
|
|
|
409 @item -I-
|
|
|
410 @opindex I-
|
|
|
411 Split the include path. Any directories specified with @option{-I}
|
|
|
412 options before @option{-I-} are searched only for headers requested with
|
|
|
413 @code{@w{#include "@var{file}"}}; they are not searched for
|
|
|
414 @code{@w{#include <@var{file}>}}. If additional directories are
|
|
|
415 specified with @option{-I} options after the @option{-I-}, those
|
|
|
416 directories are searched for all @samp{#include} directives.
|
|
|
417
|
|
|
418 In addition, @option{-I-} inhibits the use of the directory of the current
|
|
|
419 file directory as the first search directory for @code{@w{#include
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|
|
420 "@var{file}"}}.
|
|
|
421 @ifset cppmanual
|
|
|
422 @xref{Search Path}.
|
|
|
423 @end ifset
|
|
|
424 This option has been deprecated.
|
|
|
425
|
|
|
426 @item -nostdinc
|
|
|
427 @opindex nostdinc
|
|
|
428 Do not search the standard system directories for header files.
|
|
|
429 Only the directories you have specified with @option{-I} options
|
|
|
430 (and the directory of the current file, if appropriate) are searched.
|
|
|
431
|
|
|
432 @item -nostdinc++
|
|
|
433 @opindex nostdinc++
|
|
|
434 Do not search for header files in the C++-specific standard directories,
|
|
|
435 but do still search the other standard directories. (This option is
|
|
|
436 used when building the C++ library.)
|
|
|
437
|
|
|
438 @item -include @var{file}
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|
|
439 @opindex include
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|
|
440 Process @var{file} as if @code{#include "file"} appeared as the first
|
|
|
441 line of the primary source file. However, the first directory searched
|
|
|
442 for @var{file} is the preprocessor's working directory @emph{instead of}
|
|
|
443 the directory containing the main source file. If not found there, it
|
|
|
444 is searched for in the remainder of the @code{#include "@dots{}"} search
|
|
|
445 chain as normal.
|
|
|
446
|
|
|
447 If multiple @option{-include} options are given, the files are included
|
|
|
448 in the order they appear on the command line.
|
|
|
449
|
|
|
450 @item -imacros @var{file}
|
|
|
451 @opindex imacros
|
|
|
452 Exactly like @option{-include}, except that any output produced by
|
|
|
453 scanning @var{file} is thrown away. Macros it defines remain defined.
|
|
|
454 This allows you to acquire all the macros from a header without also
|
|
|
455 processing its declarations.
|
|
|
456
|
|
|
457 All files specified by @option{-imacros} are processed before all files
|
|
|
458 specified by @option{-include}.
|
|
|
459
|
|
|
460 @item -idirafter @var{dir}
|
|
|
461 @opindex idirafter
|
|
|
462 Search @var{dir} for header files, but do it @emph{after} all
|
|
|
463 directories specified with @option{-I} and the standard system directories
|
|
|
464 have been exhausted. @var{dir} is treated as a system include directory.
|
|
|
465 If @var{dir} begins with @code{=}, then the @code{=} will be replaced
|
|
|
466 by the sysroot prefix; see @option{--sysroot} and @option{-isysroot}.
|
|
|
467
|
|
|
468 @item -iprefix @var{prefix}
|
|
|
469 @opindex iprefix
|
|
|
470 Specify @var{prefix} as the prefix for subsequent @option{-iwithprefix}
|
|
|
471 options. If the prefix represents a directory, you should include the
|
|
|
472 final @samp{/}.
|
|
|
473
|
|
|
474 @item -iwithprefix @var{dir}
|
|
|
475 @itemx -iwithprefixbefore @var{dir}
|
|
|
476 @opindex iwithprefix
|
|
|
477 @opindex iwithprefixbefore
|
|
|
478 Append @var{dir} to the prefix specified previously with
|
|
|
479 @option{-iprefix}, and add the resulting directory to the include search
|
|
|
480 path. @option{-iwithprefixbefore} puts it in the same place @option{-I}
|
|
|
481 would; @option{-iwithprefix} puts it where @option{-idirafter} would.
|
|
|
482
|
|
|
483 @item -isysroot @var{dir}
|
|
|
484 @opindex isysroot
|
|
|
485 This option is like the @option{--sysroot} option, but applies only to
|
|
|
486 header files. See the @option{--sysroot} option for more information.
|
|
|
487
|
|
|
488 @item -imultilib @var{dir}
|
|
|
489 @opindex imultilib
|
|
|
490 Use @var{dir} as a subdirectory of the directory containing
|
|
|
491 target-specific C++ headers.
|
|
|
492
|
|
|
493 @item -isystem @var{dir}
|
|
|
494 @opindex isystem
|
|
|
495 Search @var{dir} for header files, after all directories specified by
|
|
|
496 @option{-I} but before the standard system directories. Mark it
|
|
|
497 as a system directory, so that it gets the same special treatment as
|
|
|
498 is applied to the standard system directories.
|
|
|
499 @ifset cppmanual
|
|
|
500 @xref{System Headers}.
|
|
|
501 @end ifset
|
|
|
502 If @var{dir} begins with @code{=}, then the @code{=} will be replaced
|
|
|
503 by the sysroot prefix; see @option{--sysroot} and @option{-isysroot}.
|
|
|
504
|
|
|
505 @item -iquote @var{dir}
|
|
|
506 @opindex iquote
|
|
|
507 Search @var{dir} only for header files requested with
|
|
|
508 @code{@w{#include "@var{file}"}}; they are not searched for
|
|
|
509 @code{@w{#include <@var{file}>}}, before all directories specified by
|
|
|
510 @option{-I} and before the standard system directories.
|
|
|
511 @ifset cppmanual
|
|
|
512 @xref{Search Path}.
|
|
|
513 @end ifset
|
|
|
514 If @var{dir} begins with @code{=}, then the @code{=} will be replaced
|
|
|
515 by the sysroot prefix; see @option{--sysroot} and @option{-isysroot}.
|
|
|
516
|
|
|
517 @item -fdirectives-only
|
|
|
518 @opindex fdirectives-only
|
|
|
519 When preprocessing, handle directives, but do not expand macros.
|
|
|
520
|
|
|
521 The option's behavior depends on the @option{-E} and @option{-fpreprocessed}
|
|
|
522 options.
|
|
|
523
|
|
|
524 With @option{-E}, preprocessing is limited to the handling of directives
|
|
|
525 such as @code{#define}, @code{#ifdef}, and @code{#error}. Other
|
|
|
526 preprocessor operations, such as macro expansion and trigraph
|
|
|
527 conversion are not performed. In addition, the @option{-dD} option is
|
|
|
528 implicitly enabled.
|
|
|
529
|
|
|
530 With @option{-fpreprocessed}, predefinition of command line and most
|
|
|
531 builtin macros is disabled. Macros such as @code{__LINE__}, which are
|
|
|
532 contextually dependent, are handled normally. This enables compilation of
|
|
|
533 files previously preprocessed with @code{-E -fdirectives-only}.
|
|
|
534
|
|
|
535 With both @option{-E} and @option{-fpreprocessed}, the rules for
|
|
|
536 @option{-fpreprocessed} take precedence. This enables full preprocessing of
|
|
|
537 files previously preprocessed with @code{-E -fdirectives-only}.
|
|
|
538
|
|
|
539 @item -fdollars-in-identifiers
|
|
|
540 @opindex fdollars-in-identifiers
|
|
|
541 @anchor{fdollars-in-identifiers}
|
|
|
542 Accept @samp{$} in identifiers.
|
|
|
543 @ifset cppmanual
|
|
|
544 @xref{Identifier characters}.
|
|
|
545 @end ifset
|
|
|
546
|
|
|
547 @item -fextended-identifiers
|
|
|
548 @opindex fextended-identifiers
|
|
|
549 Accept universal character names in identifiers. This option is
|
|
|
550 experimental; in a future version of GCC, it will be enabled by
|
|
|
551 default for C99 and C++.
|
|
|
552
|
|
|
553 @item -fpreprocessed
|
|
|
554 @opindex fpreprocessed
|
|
|
555 Indicate to the preprocessor that the input file has already been
|
|
|
556 preprocessed. This suppresses things like macro expansion, trigraph
|
|
|
557 conversion, escaped newline splicing, and processing of most directives.
|
|
|
558 The preprocessor still recognizes and removes comments, so that you can
|
|
|
559 pass a file preprocessed with @option{-C} to the compiler without
|
|
|
560 problems. In this mode the integrated preprocessor is little more than
|
|
|
561 a tokenizer for the front ends.
|
|
|
562
|
|
|
563 @option{-fpreprocessed} is implicit if the input file has one of the
|
|
|
564 extensions @samp{.i}, @samp{.ii} or @samp{.mi}. These are the
|
|
|
565 extensions that GCC uses for preprocessed files created by
|
|
|
566 @option{-save-temps}.
|
|
|
567
|
|
|
568 @item -ftabstop=@var{width}
|
|
|
569 @opindex ftabstop
|
|
|
570 Set the distance between tab stops. This helps the preprocessor report
|
|
|
571 correct column numbers in warnings or errors, even if tabs appear on the
|
|
|
572 line. If the value is less than 1 or greater than 100, the option is
|
|
|
573 ignored. The default is 8.
|
|
|
574
|
|
|
575 @item -fexec-charset=@var{charset}
|
|
|
576 @opindex fexec-charset
|
|
|
577 @cindex character set, execution
|
|
|
578 Set the execution character set, used for string and character
|
|
|
579 constants. The default is UTF-8. @var{charset} can be any encoding
|
|
|
580 supported by the system's @code{iconv} library routine.
|
|
|
581
|
|
|
582 @item -fwide-exec-charset=@var{charset}
|
|
|
583 @opindex fwide-exec-charset
|
|
|
584 @cindex character set, wide execution
|
|
|
585 Set the wide execution character set, used for wide string and
|
|
|
586 character constants. The default is UTF-32 or UTF-16, whichever
|
|
|
587 corresponds to the width of @code{wchar_t}. As with
|
|
|
588 @option{-fexec-charset}, @var{charset} can be any encoding supported
|
|
|
589 by the system's @code{iconv} library routine; however, you will have
|
|
|
590 problems with encodings that do not fit exactly in @code{wchar_t}.
|
|
|
591
|
|
|
592 @item -finput-charset=@var{charset}
|
|
|
593 @opindex finput-charset
|
|
|
594 @cindex character set, input
|
|
|
595 Set the input character set, used for translation from the character
|
|
|
596 set of the input file to the source character set used by GCC@. If the
|
|
|
597 locale does not specify, or GCC cannot get this information from the
|
|
|
598 locale, the default is UTF-8. This can be overridden by either the locale
|
|
|
599 or this command line option. Currently the command line option takes
|
|
|
600 precedence if there's a conflict. @var{charset} can be any encoding
|
|
|
601 supported by the system's @code{iconv} library routine.
|
|
|
602
|
|
|
603 @item -fworking-directory
|
|
|
604 @opindex fworking-directory
|
|
|
605 @opindex fno-working-directory
|
|
|
606 Enable generation of linemarkers in the preprocessor output that will
|
|
|
607 let the compiler know the current working directory at the time of
|
|
|
608 preprocessing. When this option is enabled, the preprocessor will
|
|
|
609 emit, after the initial linemarker, a second linemarker with the
|
|
|
610 current working directory followed by two slashes. GCC will use this
|
|
|
611 directory, when it's present in the preprocessed input, as the
|
|
|
612 directory emitted as the current working directory in some debugging
|
|
|
613 information formats. This option is implicitly enabled if debugging
|
|
|
614 information is enabled, but this can be inhibited with the negated
|
|
|
615 form @option{-fno-working-directory}. If the @option{-P} flag is
|
|
|
616 present in the command line, this option has no effect, since no
|
|
|
617 @code{#line} directives are emitted whatsoever.
|
|
|
618
|
|
|
619 @item -fno-show-column
|
|
|
620 @opindex fno-show-column
|
|
|
621 Do not print column numbers in diagnostics. This may be necessary if
|
|
|
622 diagnostics are being scanned by a program that does not understand the
|
|
|
623 column numbers, such as @command{dejagnu}.
|
|
|
624
|
|
|
625 @item -A @var{predicate}=@var{answer}
|
|
|
626 @opindex A
|
|
|
627 Make an assertion with the predicate @var{predicate} and answer
|
|
|
628 @var{answer}. This form is preferred to the older form @option{-A
|
|
|
629 @var{predicate}(@var{answer})}, which is still supported, because
|
|
|
630 it does not use shell special characters.
|
|
|
631 @ifset cppmanual
|
|
|
632 @xref{Obsolete Features}.
|
|
|
633 @end ifset
|
|
|
634
|
|
|
635 @item -A -@var{predicate}=@var{answer}
|
|
|
636 Cancel an assertion with the predicate @var{predicate} and answer
|
|
|
637 @var{answer}.
|
|
|
638
|
|
|
639 @item -dCHARS
|
|
|
640 @var{CHARS} is a sequence of one or more of the following characters,
|
|
|
641 and must not be preceded by a space. Other characters are interpreted
|
|
|
642 by the compiler proper, or reserved for future versions of GCC, and so
|
|
|
643 are silently ignored. If you specify characters whose behavior
|
|
|
644 conflicts, the result is undefined.
|
|
|
645
|
|
|
646 @table @samp
|
|
|
647 @item M
|
|
|
648 @opindex dM
|
|
|
649 Instead of the normal output, generate a list of @samp{#define}
|
|
|
650 directives for all the macros defined during the execution of the
|
|
|
651 preprocessor, including predefined macros. This gives you a way of
|
|
|
652 finding out what is predefined in your version of the preprocessor.
|
|
|
653 Assuming you have no file @file{foo.h}, the command
|
|
|
654
|
|
|
655 @smallexample
|
|
|
656 touch foo.h; cpp -dM foo.h
|
|
|
657 @end smallexample
|
|
|
658
|
|
|
659 @noindent
|
|
|
660 will show all the predefined macros.
|
|
|
661
|
|
|
662 If you use @option{-dM} without the @option{-E} option, @option{-dM} is
|
|
|
663 interpreted as a synonym for @option{-fdump-rtl-mach}.
|
|
|
664 @xref{Debugging Options, , ,gcc}.
|
|
|
665
|
|
|
666 @item D
|
|
|
667 @opindex dD
|
|
|
668 Like @samp{M} except in two respects: it does @emph{not} include the
|
|
|
669 predefined macros, and it outputs @emph{both} the @samp{#define}
|
|
|
670 directives and the result of preprocessing. Both kinds of output go to
|
|
|
671 the standard output file.
|
|
|
672
|
|
|
673 @item N
|
|
|
674 @opindex dN
|
|
|
675 Like @samp{D}, but emit only the macro names, not their expansions.
|
|
|
676
|
|
|
677 @item I
|
|
|
678 @opindex dI
|
|
|
679 Output @samp{#include} directives in addition to the result of
|
|
|
680 preprocessing.
|
|
|
681
|
|
|
682 @item U
|
|
|
683 @opindex dU
|
|
|
684 Like @samp{D} except that only macros that are expanded, or whose
|
|
|
685 definedness is tested in preprocessor directives, are output; the
|
|
|
686 output is delayed until the use or test of the macro; and
|
|
|
687 @samp{#undef} directives are also output for macros tested but
|
|
|
688 undefined at the time.
|
|
|
689 @end table
|
|
|
690
|
|
|
691 @item -P
|
|
|
692 @opindex P
|
|
|
693 Inhibit generation of linemarkers in the output from the preprocessor.
|
|
|
694 This might be useful when running the preprocessor on something that is
|
|
|
695 not C code, and will be sent to a program which might be confused by the
|
|
|
696 linemarkers.
|
|
|
697 @ifset cppmanual
|
|
|
698 @xref{Preprocessor Output}.
|
|
|
699 @end ifset
|
|
|
700
|
|
|
701 @item -C
|
|
|
702 @opindex C
|
|
|
703 Do not discard comments. All comments are passed through to the output
|
|
|
704 file, except for comments in processed directives, which are deleted
|
|
|
705 along with the directive.
|
|
|
706
|
|
|
707 You should be prepared for side effects when using @option{-C}; it
|
|
|
708 causes the preprocessor to treat comments as tokens in their own right.
|
|
|
709 For example, comments appearing at the start of what would be a
|
|
|
710 directive line have the effect of turning that line into an ordinary
|
|
|
711 source line, since the first token on the line is no longer a @samp{#}.
|
|
|
712
|
|
|
713 @item -CC
|
|
|
714 Do not discard comments, including during macro expansion. This is
|
|
|
715 like @option{-C}, except that comments contained within macros are
|
|
|
716 also passed through to the output file where the macro is expanded.
|
|
|
717
|
|
|
718 In addition to the side-effects of the @option{-C} option, the
|
|
|
719 @option{-CC} option causes all C++-style comments inside a macro
|
|
|
720 to be converted to C-style comments. This is to prevent later use
|
|
|
721 of that macro from inadvertently commenting out the remainder of
|
|
|
722 the source line.
|
|
|
723
|
|
|
724 The @option{-CC} option is generally used to support lint comments.
|
|
|
725
|
|
|
726 @item -traditional-cpp
|
|
|
727 @opindex traditional-cpp
|
|
|
728 Try to imitate the behavior of old-fashioned C preprocessors, as
|
|
|
729 opposed to ISO C preprocessors.
|
|
|
730 @ifset cppmanual
|
|
|
731 @xref{Traditional Mode}.
|
|
|
732 @end ifset
|
|
|
733
|
|
|
734 @item -trigraphs
|
|
|
735 @opindex trigraphs
|
|
|
736 Process trigraph sequences.
|
|
|
737 @ifset cppmanual
|
|
|
738 @xref{Initial processing}.
|
|
|
739 @end ifset
|
|
|
740 @ifclear cppmanual
|
|
|
741 These are three-character sequences, all starting with @samp{??}, that
|
|
|
742 are defined by ISO C to stand for single characters. For example,
|
|
|
743 @samp{??/} stands for @samp{\}, so @samp{'??/n'} is a character
|
|
|
744 constant for a newline. By default, GCC ignores trigraphs, but in
|
|
|
745 standard-conforming modes it converts them. See the @option{-std} and
|
|
|
746 @option{-ansi} options.
|
|
|
747
|
|
|
748 The nine trigraphs and their replacements are
|
|
|
749
|
|
|
750 @smallexample
|
|
|
751 Trigraph: ??( ??) ??< ??> ??= ??/ ??' ??! ??-
|
|
|
752 Replacement: [ ] @{ @} # \ ^ | ~
|
|
|
753 @end smallexample
|
|
|
754 @end ifclear
|
|
|
755
|
|
|
756 @item -remap
|
|
|
757 @opindex remap
|
|
|
758 Enable special code to work around file systems which only permit very
|
|
|
759 short file names, such as MS-DOS@.
|
|
|
760
|
|
|
761 @itemx --help
|
|
|
762 @itemx --target-help
|
|
|
763 @opindex help
|
|
|
764 @opindex target-help
|
|
|
765 Print text describing all the command line options instead of
|
|
|
766 preprocessing anything.
|
|
|
767
|
|
|
768 @item -v
|
|
|
769 @opindex v
|
|
|
770 Verbose mode. Print out GNU CPP's version number at the beginning of
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771 execution, and report the final form of the include path.
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772
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773 @item -H
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774 @opindex H
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775 Print the name of each header file used, in addition to other normal
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776 activities. Each name is indented to show how deep in the
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777 @samp{#include} stack it is. Precompiled header files are also
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778 printed, even if they are found to be invalid; an invalid precompiled
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779 header file is printed with @samp{...x} and a valid one with @samp{...!} .
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780
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781 @item -version
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782 @itemx --version
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783 @opindex version
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784 Print out GNU CPP's version number. With one dash, proceed to
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785 preprocess as normal. With two dashes, exit immediately.
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786 @end table
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