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132 .\" ========================================================================
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133 .\"
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134 .IX Title "GCJ 1"
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135 .TH GCJ 1 "2009-04-21" "gcc-4.4.0" "GNU"
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136 .\" For nroff, turn off justification. Always turn off hyphenation; it makes
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137 .\" way too many mistakes in technical documents.
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138 .if n .ad l
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139 .nh
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140 .SH "NAME"
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141 gcj \- Ahead\-of\-time compiler for the Java language
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142 .SH "SYNOPSIS"
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143 .IX Header "SYNOPSIS"
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144 gcj [\fB\-I\fR\fIdir\fR...] [\fB\-d\fR \fIdir\fR...]
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145 [\fB\-\-CLASSPATH\fR=\fIpath\fR] [\fB\-\-classpath\fR=\fIpath\fR]
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146 [\fB\-f\fR\fIoption\fR...] [\fB\-\-encoding\fR=\fIname\fR]
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147 [\fB\-\-main\fR=\fIclassname\fR] [\fB\-D\fR\fIname\fR[=\fIvalue\fR]...]
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148 [\fB\-C\fR] [\fB\-\-resource\fR \fIresource-name\fR] [\fB\-d\fR \fIdirectory\fR]
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149 [\fB\-W\fR\fIwarn\fR...]
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150 \fIsourcefile\fR...
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151 .SH "DESCRIPTION"
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152 .IX Header "DESCRIPTION"
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153 As \fBgcj\fR is just another front end to \fBgcc\fR, it supports many
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154 of the same options as gcc. This manual only documents the
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155 options specific to \fBgcj\fR.
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156 .SH "OPTIONS"
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157 .IX Header "OPTIONS"
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158 .Sh "Input and output files"
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159 .IX Subsection "Input and output files"
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160 A \fBgcj\fR command is like a \fBgcc\fR command, in that it
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161 consists of a number of options and file names. The following kinds
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162 of input file names are supported:
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163 .IP "\fIfile\fR\fB.java\fR" 4
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164 .IX Item "file.java"
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165 Java source files.
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166 .IP "\fIfile\fR\fB.class\fR" 4
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167 .IX Item "file.class"
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168 Java bytecode files.
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169 .IP "\fIfile\fR\fB.zip\fR" 4
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170 .IX Item "file.zip"
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171 .PD 0
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172 .IP "\fIfile\fR\fB.jar\fR" 4
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173 .IX Item "file.jar"
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174 .PD
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175 An archive containing one or more \f(CW\*(C`.class\*(C'\fR files, all of
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176 which are compiled. The archive may be compressed. Files in
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177 an archive which don't end with \fB.class\fR are treated as
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178 resource files; they are compiled into the resulting object file
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179 as \fBcore:\fR URLs.
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180 .IP "\fB@\fR\fIfile\fR" 4
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181 .IX Item "@file"
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182 A file containing a whitespace-separated list of input file names.
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183 (Currently, these must all be \f(CW\*(C`.java\*(C'\fR source files, but that
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184 may change.)
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185 Each named file is compiled, just as if it had been on the command line.
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186 .IP "\fIlibrary\fR\fB.a\fR" 4
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187 .IX Item "library.a"
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188 .PD 0
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189 .IP "\fIlibrary\fR\fB.so\fR" 4
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190 .IX Item "library.so"
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191 .IP "\fB\-l\fR\fIlibname\fR" 4
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192 .IX Item "-llibname"
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193 .PD
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194 Libraries to use when linking. See the \fBgcc\fR manual.
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195 .PP
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196 You can specify more than one input file on the \fBgcj\fR command line,
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197 in which case they will all be compiled. If you specify a
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198 \&\f(CW\*(C`\-o \f(CIFILENAME\f(CW\*(C'\fR
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199 option, all the input files will be compiled together, producing a
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200 single output file, named \fI\s-1FILENAME\s0\fR.
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201 This is allowed even when using \f(CW\*(C`\-S\*(C'\fR or \f(CW\*(C`\-c\*(C'\fR,
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202 but not when using \f(CW\*(C`\-C\*(C'\fR or \f(CW\*(C`\-\-resource\*(C'\fR.
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203 (This is an extension beyond the what plain \fBgcc\fR allows.)
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204 (If more than one input file is specified, all must currently
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205 be \f(CW\*(C`.java\*(C'\fR files, though we hope to fix this.)
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206 .Sh "Input Options"
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207 .IX Subsection "Input Options"
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208 \&\fBgcj\fR has options to control where it looks to find files it needs.
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209 For instance, \fBgcj\fR might need to load a class that is referenced
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210 by the file it has been asked to compile. Like other compilers for the
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211 Java language, \fBgcj\fR has a notion of a \fIclass path\fR. There are
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212 several options and environment variables which can be used to
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213 manipulate the class path. When \fBgcj\fR looks for a given class, it
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214 searches the class path looking for matching \fI.class\fR or
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215 \&\fI.java\fR file. \fBgcj\fR comes with a built-in class path which
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216 points at the installed \fIlibgcj.jar\fR, a file which contains all the
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217 standard classes.
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218 .PP
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219 In the text below, a directory or path component can refer either to an
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220 actual directory on the filesystem, or to a \fI.zip\fR or \fI.jar\fR
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221 file, which \fBgcj\fR will search as if it is a directory.
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222 .IP "\fB\-I\fR\fIdir\fR" 4
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223 .IX Item "-Idir"
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224 All directories specified by \f(CW\*(C`\-I\*(C'\fR are kept in order and prepended
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225 to the class path constructed from all the other options. Unless
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226 compatibility with tools like \f(CW\*(C`javac\*(C'\fR is important, we recommend
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227 always using \f(CW\*(C`\-I\*(C'\fR instead of the other options for manipulating the
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228 class path.
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229 .IP "\fB\-\-classpath=\fR\fIpath\fR" 4
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230 .IX Item "--classpath=path"
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231 This sets the class path to \fIpath\fR, a colon-separated list of paths
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232 (on Windows-based systems, a semicolon-separate list of paths).
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233 This does not override the builtin (\*(L"boot\*(R") search path.
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234 .IP "\fB\-\-CLASSPATH=\fR\fIpath\fR" 4
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235 .IX Item "--CLASSPATH=path"
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236 Deprecated synonym for \f(CW\*(C`\-\-classpath\*(C'\fR.
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237 .IP "\fB\-\-bootclasspath=\fR\fIpath\fR" 4
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238 .IX Item "--bootclasspath=path"
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239 Where to find the standard builtin classes, such as \f(CW\*(C`java.lang.String\*(C'\fR.
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240 .IP "\fB\-\-extdirs=\fR\fIpath\fR" 4
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241 .IX Item "--extdirs=path"
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242 For each directory in the \fIpath\fR, place the contents of that
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243 directory at the end of the class path.
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244 .IP "\fB\s-1CLASSPATH\s0\fR" 4
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245 .IX Item "CLASSPATH"
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246 This is an environment variable which holds a list of paths.
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247 .PP
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248 The final class path is constructed like so:
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249 .IP "\(bu" 4
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250 First come all directories specified via \f(CW\*(C`\-I\*(C'\fR.
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251 .IP "\(bu" 4
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252 If \fB\-\-classpath\fR is specified, its value is appended.
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253 Otherwise, if the \f(CW\*(C`CLASSPATH\*(C'\fR environment variable is specified,
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254 then its value is appended.
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255 Otherwise, the current directory (\f(CW"."\fR) is appended.
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256 .IP "\(bu" 4
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257 If \f(CW\*(C`\-\-bootclasspath\*(C'\fR was specified, append its value.
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258 Otherwise, append the built-in system directory, \fIlibgcj.jar\fR.
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259 .IP "\(bu" 4
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260 Finally, if \f(CW\*(C`\-\-extdirs\*(C'\fR was specified, append the contents of the
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261 specified directories at the end of the class path. Otherwise, append
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262 the contents of the built-in extdirs at \f(CW\*(C`$(prefix)/share/java/ext\*(C'\fR.
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263 .PP
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264 The classfile built by \fBgcj\fR for the class \f(CW\*(C`java.lang.Object\*(C'\fR
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265 (and placed in \f(CW\*(C`libgcj.jar\*(C'\fR) contains a special zero length
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266 attribute \f(CW\*(C`gnu.gcj.gcj\-compiled\*(C'\fR. The compiler looks for this
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267 attribute when loading \f(CW\*(C`java.lang.Object\*(C'\fR and will report an error
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268 if it isn't found, unless it compiles to bytecode (the option
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269 \&\f(CW\*(C`\-fforce\-classes\-archive\-check\*(C'\fR can be used to override this
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270 behavior in this particular case.)
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271 .IP "\fB\-fforce\-classes\-archive\-check\fR" 4
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272 .IX Item "-fforce-classes-archive-check"
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273 This forces the compiler to always check for the special zero length
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274 attribute \f(CW\*(C`gnu.gcj.gcj\-compiled\*(C'\fR in \f(CW\*(C`java.lang.Object\*(C'\fR and
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275 issue an error if it isn't found.
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276 .IP "\fB\-fsource=\fR\fI\s-1VERSION\s0\fR" 4
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277 .IX Item "-fsource=VERSION"
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278 This option is used to choose the source version accepted by
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279 \&\fBgcj\fR. The default is \fB1.5\fR.
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280 .Sh "Encodings"
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281 .IX Subsection "Encodings"
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282 The Java programming language uses Unicode throughout. In an effort to
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283 integrate well with other locales, \fBgcj\fR allows \fI.java\fR files
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284 to be written using almost any encoding. \fBgcj\fR knows how to
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285 convert these encodings into its internal encoding at compile time.
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286 .PP
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287 You can use the \f(CW\*(C`\-\-encoding=\f(CINAME\f(CW\*(C'\fR option to specify an
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288 encoding (of a particular character set) to use for source files. If
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289 this is not specified, the default encoding comes from your current
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290 locale. If your host system has insufficient locale support, then
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291 \&\fBgcj\fR assumes the default encoding to be the \fB\s-1UTF\-8\s0\fR encoding
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292 of Unicode.
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293 .PP
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294 To implement \f(CW\*(C`\-\-encoding\*(C'\fR, \fBgcj\fR simply uses the host
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295 platform's \f(CW\*(C`iconv\*(C'\fR conversion routine. This means that in practice
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296 \&\fBgcj\fR is limited by the capabilities of the host platform.
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297 .PP
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298 The names allowed for the argument \f(CW\*(C`\-\-encoding\*(C'\fR vary from platform
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299 to platform (since they are not standardized anywhere). However,
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300 \&\fBgcj\fR implements the encoding named \fB\s-1UTF\-8\s0\fR internally, so if
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301 you choose to use this for your source files you can be assured that it
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302 will work on every host.
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303 .Sh "Warnings"
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304 .IX Subsection "Warnings"
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305 \&\fBgcj\fR implements several warnings. As with other generic
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306 \&\fBgcc\fR warnings, if an option of the form \f(CW\*(C`\-Wfoo\*(C'\fR enables a
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307 warning, then \f(CW\*(C`\-Wno\-foo\*(C'\fR will disable it. Here we've chosen to
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308 document the form of the warning which will have an effect \*(-- the
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309 default being the opposite of what is listed.
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310 .IP "\fB\-Wredundant\-modifiers\fR" 4
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311 .IX Item "-Wredundant-modifiers"
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312 With this flag, \fBgcj\fR will warn about redundant modifiers. For
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313 instance, it will warn if an interface method is declared \f(CW\*(C`public\*(C'\fR.
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314 .IP "\fB\-Wextraneous\-semicolon\fR" 4
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315 .IX Item "-Wextraneous-semicolon"
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316 This causes \fBgcj\fR to warn about empty statements. Empty statements
|
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317 have been deprecated.
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318 .IP "\fB\-Wno\-out\-of\-date\fR" 4
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319 .IX Item "-Wno-out-of-date"
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320 This option will cause \fBgcj\fR not to warn when a source file is
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321 newer than its matching class file. By default \fBgcj\fR will warn
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322 about this.
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323 .IP "\fB\-Wno\-deprecated\fR" 4
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324 .IX Item "-Wno-deprecated"
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325 Warn if a deprecated class, method, or field is referred to.
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326 .IP "\fB\-Wunused\fR" 4
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327 .IX Item "-Wunused"
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328 This is the same as \fBgcc\fR's \f(CW\*(C`\-Wunused\*(C'\fR.
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329 .IP "\fB\-Wall\fR" 4
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330 .IX Item "-Wall"
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331 This is the same as \f(CW\*(C`\-Wredundant\-modifiers \-Wextraneous\-semicolon
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332 \&\-Wunused\*(C'\fR.
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333 .Sh "Linking"
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334 .IX Subsection "Linking"
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335 To turn a Java application into an executable program,
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336 you need to link it with the needed libraries, just as for C or \*(C+.
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337 The linker by default looks for a global function named \f(CW\*(C`main\*(C'\fR.
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338 Since Java does not have global functions, and a
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339 collection of Java classes may have more than one class with a
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340 \&\f(CW\*(C`main\*(C'\fR method, you need to let the linker know which of those
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341 \&\f(CW\*(C`main\*(C'\fR methods it should invoke when starting the application.
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342 You can do that in any of these ways:
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343 .IP "\(bu" 4
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344 Specify the class containing the desired \f(CW\*(C`main\*(C'\fR method
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345 when you link the application, using the \f(CW\*(C`\-\-main\*(C'\fR flag,
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346 described below.
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347 .IP "\(bu" 4
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348 Link the Java package(s) into a shared library (dll) rather than an
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349 executable. Then invoke the application using the \f(CW\*(C`gij\*(C'\fR program,
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350 making sure that \f(CW\*(C`gij\*(C'\fR can find the libraries it needs.
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351 .IP "\(bu" 4
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352 Link the Java packages(s) with the flag \f(CW\*(C`\-lgij\*(C'\fR, which links
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353 in the \f(CW\*(C`main\*(C'\fR routine from the \f(CW\*(C`gij\*(C'\fR command.
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354 This allows you to select the class whose \f(CW\*(C`main\*(C'\fR method you
|
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355 want to run when you run the application. You can also use
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356 other \f(CW\*(C`gij\*(C'\fR flags, such as \f(CW\*(C`\-D\*(C'\fR flags to set properties.
|
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357 Using the \f(CW\*(C`\-lgij\*(C'\fR library (rather than the \f(CW\*(C`gij\*(C'\fR program
|
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358 of the previous mechanism) has some advantages: it is compatible with
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359 static linking, and does not require configuring or installing libraries.
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360 .PP
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361 These \f(CW\*(C`gij\*(C'\fR options relate to linking an executable:
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362 .IP "\fB\-\-main=\fR\fI\s-1CLASSNAME\s0\fR" 4
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363 .IX Item "--main=CLASSNAME"
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364 This option is used when linking to specify the name of the class whose
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365 \&\f(CW\*(C`main\*(C'\fR method should be invoked when the resulting executable is
|
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366 run.
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367 .IP "\fB\-D\fR\fIname\fR\fB[=\fR\fIvalue\fR\fB]\fR" 4
|
|
368 .IX Item "-Dname[=value]"
|
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369 This option can only be used with \f(CW\*(C`\-\-main\*(C'\fR. It defines a system
|
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370 property named \fIname\fR with value \fIvalue\fR. If \fIvalue\fR is not
|
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371 specified then it defaults to the empty string. These system properties
|
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372 are initialized at the program's startup and can be retrieved at runtime
|
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373 using the \f(CW\*(C`java.lang.System.getProperty\*(C'\fR method.
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374 .IP "\fB\-lgij\fR" 4
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375 .IX Item "-lgij"
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376 Create an application whose command-line processing is that
|
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377 of the \f(CW\*(C`gij\*(C'\fR command.
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378 .Sp
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379 This option is an alternative to using \f(CW\*(C`\-\-main\*(C'\fR; you cannot use both.
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380 .IP "\fB\-static\-libgcj\fR" 4
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|
381 .IX Item "-static-libgcj"
|
|
382 This option causes linking to be done against a static version of the
|
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383 libgcj runtime library. This option is only available if
|
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384 corresponding linker support exists.
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385 .Sp
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386 \&\fBCaution:\fR Static linking of libgcj may cause essential parts
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387 of libgcj to be omitted. Some parts of libgcj use reflection to load
|
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388 classes at runtime. Since the linker does not see these references at
|
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389 link time, it can omit the referred to classes. The result is usually
|
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390 (but not always) a \f(CW\*(C`ClassNotFoundException\*(C'\fR being thrown at
|
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391 runtime. Caution must be used when using this option. For more
|
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392 details see:
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393 <\fBhttp://gcc.gnu.org/wiki/Statically%20linking%20libgcj\fR>
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394 .Sh "Code Generation"
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395 .IX Subsection "Code Generation"
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396 In addition to the many \fBgcc\fR options controlling code generation,
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397 \&\fBgcj\fR has several options specific to itself.
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398 .IP "\fB\-C\fR" 4
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|
399 .IX Item "-C"
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400 This option is used to tell \fBgcj\fR to generate bytecode
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401 (\fI.class\fR files) rather than object code.
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402 .IP "\fB\-\-resource\fR \fIresource-name\fR" 4
|
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403 .IX Item "--resource resource-name"
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404 This option is used to tell \fBgcj\fR to compile the contents of a
|
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405 given file to object code so it may be accessed at runtime with the core
|
|
406 protocol handler as \fBcore:/\fR\fIresource-name\fR. Note that
|
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407 \&\fIresource-name\fR is the name of the resource as found at runtime; for
|
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408 instance, it could be used in a call to \f(CW\*(C`ResourceBundle.getBundle\*(C'\fR.
|
|
409 The actual file name to be compiled this way must be specified
|
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410 separately.
|
|
411 .IP "\fB\-ftarget=\fR\fI\s-1VERSION\s0\fR" 4
|
|
412 .IX Item "-ftarget=VERSION"
|
|
413 This can be used with \fB\-C\fR to choose the version of bytecode
|
|
414 emitted by \fBgcj\fR. The default is \fB1.5\fR. When not
|
|
415 generating bytecode, this option has no effect.
|
|
416 .IP "\fB\-d\fR \fIdirectory\fR" 4
|
|
417 .IX Item "-d directory"
|
|
418 When used with \f(CW\*(C`\-C\*(C'\fR, this causes all generated \fI.class\fR files
|
|
419 to be put in the appropriate subdirectory of \fIdirectory\fR. By
|
|
420 default they will be put in subdirectories of the current working
|
|
421 directory.
|
|
422 .IP "\fB\-fno\-bounds\-check\fR" 4
|
|
423 .IX Item "-fno-bounds-check"
|
|
424 By default, \fBgcj\fR generates code which checks the bounds of all
|
|
425 array indexing operations. With this option, these checks are omitted, which
|
|
426 can improve performance for code that uses arrays extensively. Note that this
|
|
427 can result in unpredictable behavior if the code in question actually does
|
|
428 violate array bounds constraints. It is safe to use this option if you are
|
|
429 sure that your code will never throw an \f(CW\*(C`ArrayIndexOutOfBoundsException\*(C'\fR.
|
|
430 .IP "\fB\-fno\-store\-check\fR" 4
|
|
431 .IX Item "-fno-store-check"
|
|
432 Don't generate array store checks. When storing objects into arrays, a runtime
|
|
433 check is normally generated in order to ensure that the object is assignment
|
|
434 compatible with the component type of the array (which may not be known
|
|
435 at compile-time). With this option, these checks are omitted. This can
|
|
436 improve performance for code which stores objects into arrays frequently.
|
|
437 It is safe to use this option if you are sure your code will never throw an
|
|
438 \&\f(CW\*(C`ArrayStoreException\*(C'\fR.
|
|
439 .IP "\fB\-fjni\fR" 4
|
|
440 .IX Item "-fjni"
|
|
441 With \fBgcj\fR there are two options for writing native methods: \s-1CNI\s0
|
|
442 and \s-1JNI\s0. By default \fBgcj\fR assumes you are using \s-1CNI\s0. If you are
|
|
443 compiling a class with native methods, and these methods are implemented
|
|
444 using \s-1JNI\s0, then you must use \f(CW\*(C`\-fjni\*(C'\fR. This option causes
|
|
445 \&\fBgcj\fR to generate stubs which will invoke the underlying \s-1JNI\s0
|
|
446 methods.
|
|
447 .IP "\fB\-fno\-assert\fR" 4
|
|
448 .IX Item "-fno-assert"
|
|
449 Don't recognize the \f(CW\*(C`assert\*(C'\fR keyword. This is for compatibility
|
|
450 with older versions of the language specification.
|
|
451 .IP "\fB\-fno\-optimize\-static\-class\-initialization\fR" 4
|
|
452 .IX Item "-fno-optimize-static-class-initialization"
|
|
453 When the optimization level is greater or equal to \f(CW\*(C`\-O2\*(C'\fR,
|
|
454 \&\fBgcj\fR will try to optimize the way calls into the runtime are made
|
|
455 to initialize static classes upon their first use (this optimization
|
|
456 isn't carried out if \f(CW\*(C`\-C\*(C'\fR was specified.) When compiling to native
|
|
457 code, \f(CW\*(C`\-fno\-optimize\-static\-class\-initialization\*(C'\fR will turn this
|
|
458 optimization off, regardless of the optimization level in use.
|
|
459 .IP "\fB\-\-disable\-assertions[=\fR\fIclass-or-package\fR\fB]\fR" 4
|
|
460 .IX Item "--disable-assertions[=class-or-package]"
|
|
461 Don't include code for checking assertions in the compiled code.
|
|
462 If \f(CW\*(C`=\f(CIclass\-or\-package\f(CW\*(C'\fR is missing disables assertion code
|
|
463 generation for all classes, unless overridden by a more
|
|
464 specific \f(CW\*(C`\-\-enable\-assertions\*(C'\fR flag.
|
|
465 If \fIclass-or-package\fR is a class name, only disables generating
|
|
466 assertion checks within the named class or its inner classes.
|
|
467 If \fIclass-or-package\fR is a package name, disables generating
|
|
468 assertion checks within the named package or a subpackage.
|
|
469 .Sp
|
|
470 By default, assertions are enabled when generating class files
|
|
471 or when not optimizing, and disabled when generating optimized binaries.
|
|
472 .IP "\fB\-\-enable\-assertions[=\fR\fIclass-or-package\fR\fB]\fR" 4
|
|
473 .IX Item "--enable-assertions[=class-or-package]"
|
|
474 Generates code to check assertions. The option is perhaps misnamed,
|
|
475 as you still need to turn on assertion checking at run-time,
|
|
476 and we don't support any easy way to do that.
|
|
477 So this flag isn't very useful yet, except to partially override
|
|
478 \&\f(CW\*(C`\-\-disable\-assertions\*(C'\fR.
|
|
479 .IP "\fB\-findirect\-dispatch\fR" 4
|
|
480 .IX Item "-findirect-dispatch"
|
|
481 \&\fBgcj\fR has a special binary compatibility \s-1ABI\s0, which is enabled
|
|
482 by the \f(CW\*(C`\-findirect\-dispatch\*(C'\fR option. In this mode, the code
|
|
483 generated by \fBgcj\fR honors the binary compatibility guarantees
|
|
484 in the Java Language Specification, and the resulting object files do
|
|
485 not need to be directly linked against their dependencies. Instead,
|
|
486 all dependencies are looked up at runtime. This allows free mixing of
|
|
487 interpreted and compiled code.
|
|
488 .Sp
|
|
489 Note that, at present, \f(CW\*(C`\-findirect\-dispatch\*(C'\fR can only be used
|
|
490 when compiling \fI.class\fR files. It will not work when compiling
|
|
491 from source. \s-1CNI\s0 also does not yet work with the binary compatibility
|
|
492 \&\s-1ABI\s0. These restrictions will be lifted in some future release.
|
|
493 .Sp
|
|
494 However, if you compile \s-1CNI\s0 code with the standard \s-1ABI\s0, you can call
|
|
495 it from code built with the binary compatibility \s-1ABI\s0.
|
|
496 .IP "\fB\-fbootstrap\-classes\fR" 4
|
|
497 .IX Item "-fbootstrap-classes"
|
|
498 This option can be use to tell \f(CW\*(C`libgcj\*(C'\fR that the compiled classes
|
|
499 should be loaded by the bootstrap loader, not the system class loader.
|
|
500 By default, if you compile a class and link it into an executable, it
|
|
501 will be treated as if it was loaded using the system class loader.
|
|
502 This is convenient, as it means that things like
|
|
503 \&\f(CW\*(C`Class.forName()\*(C'\fR will search \fB\s-1CLASSPATH\s0\fR to find the
|
|
504 desired class.
|
|
505 .IP "\fB\-freduced\-reflection\fR" 4
|
|
506 .IX Item "-freduced-reflection"
|
|
507 This option causes the code generated by \fBgcj\fR to contain a
|
|
508 reduced amount of the class meta-data used to support runtime
|
|
509 reflection. The cost of this savings is the loss of
|
|
510 the ability to use certain reflection capabilities of the standard
|
|
511 Java runtime environment. When set all meta-data except for that
|
|
512 which is needed to obtain correct runtime semantics is eliminated.
|
|
513 .Sp
|
|
514 For code that does not use reflection (i.e. serialization, \s-1RMI\s0, \s-1CORBA\s0
|
|
515 or call methods in the \f(CW\*(C`java.lang.reflect\*(C'\fR package),
|
|
516 \&\f(CW\*(C`\-freduced\-reflection\*(C'\fR will result in proper operation with a
|
|
517 savings in executable code size.
|
|
518 .Sp
|
|
519 \&\s-1JNI\s0 (\f(CW\*(C`\-fjni\*(C'\fR) and the binary compatibility \s-1ABI\s0
|
|
520 (\f(CW\*(C`\-findirect\-dispatch\*(C'\fR) do not work properly without full
|
|
521 reflection meta-data. Because of this, it is an error to use these options
|
|
522 with \f(CW\*(C`\-freduced\-reflection\*(C'\fR.
|
|
523 .Sp
|
|
524 \&\fBCaution:\fR If there is no reflection meta-data, code that uses
|
|
525 a \f(CW\*(C`SecurityManager\*(C'\fR may not work properly. Also calling
|
|
526 \&\f(CW\*(C`Class.forName()\*(C'\fR may fail if the calling method has no
|
|
527 reflection meta-data.
|
|
528 .Sh "Configure-time Options"
|
|
529 .IX Subsection "Configure-time Options"
|
|
530 Some \fBgcj\fR code generations options affect the resulting \s-1ABI\s0, and
|
|
531 so can only be meaningfully given when \f(CW\*(C`libgcj\*(C'\fR, the runtime
|
|
532 package, is configured. \f(CW\*(C`libgcj\*(C'\fR puts the appropriate options from
|
|
533 this group into a \fBspec\fR file which is read by \fBgcj\fR. These
|
|
534 options are listed here for completeness; if you are using \f(CW\*(C`libgcj\*(C'\fR
|
|
535 then you won't want to touch these options.
|
|
536 .IP "\fB\-fuse\-boehm\-gc\fR" 4
|
|
537 .IX Item "-fuse-boehm-gc"
|
|
538 This enables the use of the Boehm \s-1GC\s0 bitmap marking code. In particular
|
|
539 this causes \fBgcj\fR to put an object marking descriptor into each
|
|
540 vtable.
|
|
541 .IP "\fB\-fhash\-synchronization\fR" 4
|
|
542 .IX Item "-fhash-synchronization"
|
|
543 By default, synchronization data (the data used for \f(CW\*(C`synchronize\*(C'\fR,
|
|
544 \&\f(CW\*(C`wait\*(C'\fR, and \f(CW\*(C`notify\*(C'\fR) is pointed to by a word in each object.
|
|
545 With this option \fBgcj\fR assumes that this information is stored in a
|
|
546 hash table and not in the object itself.
|
|
547 .IP "\fB\-fuse\-divide\-subroutine\fR" 4
|
|
548 .IX Item "-fuse-divide-subroutine"
|
|
549 On some systems, a library routine is called to perform integer
|
|
550 division. This is required to get exception handling correct when
|
|
551 dividing by zero.
|
|
552 .IP "\fB\-fcheck\-references\fR" 4
|
|
553 .IX Item "-fcheck-references"
|
|
554 On some systems it's necessary to insert inline checks whenever
|
|
555 accessing an object via a reference. On other systems you won't need
|
|
556 this because null pointer accesses are caught automatically by the
|
|
557 processor.
|
|
558 .SH "SEE ALSO"
|
|
559 .IX Header "SEE ALSO"
|
|
560 \&\fIgcc\fR\|(1), \fIgcjh\fR\|(1), \fIgjnih\fR\|(1), \fIgij\fR\|(1), \fIjcf\-dump\fR\|(1), \fIgfdl\fR\|(7),
|
|
561 and the Info entries for \fIgcj\fR and \fIgcc\fR.
|
|
562 .SH "COPYRIGHT"
|
|
563 .IX Header "COPYRIGHT"
|
|
564 Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
|
|
565 .PP
|
|
566 Permission is granted to copy, distribute and/or modify this document
|
|
567 under the terms of the \s-1GNU\s0 Free Documentation License, Version 1.2 or
|
|
568 any later version published by the Free Software Foundation; with no
|
|
569 Invariant Sections, the Front-Cover Texts being (a) (see below), and
|
|
570 with the Back-Cover Texts being (b) (see below).
|
|
571 A copy of the license is included in the
|
|
572 man page \fIgfdl\fR\|(7).
|
|
573 .PP
|
|
574 (a) The \s-1FSF\s0's Front-Cover Text is:
|
|
575 .PP
|
|
576 .Vb 1
|
|
577 \& A GNU Manual
|
|
578 .Ve
|
|
579 .PP
|
|
580 (b) The \s-1FSF\s0's Back-Cover Text is:
|
|
581 .PP
|
|
582 .Vb 3
|
|
583 \& You have freedom to copy and modify this GNU Manual, like GNU
|
|
584 \& software. Copies published by the Free Software Foundation raise
|
|
585 \& funds for GNU development.
|
|
586 .Ve
|