javah(1) javah(1)

NAME
       javah - C header and stub file generator

SYNOPSIS
       jjaavvaahh [ options ] fully-qualified-classname ...
       jjaavvaahhgg [ options ] fully-qualified-classname ...

DESCRIPTION
       The  jjaavvaahh  command generates C header and source files that are needed
       to implement native methods. The generated header and source files  are
       used  by  C  programs to reference instance variables of an object from
       native source code. The ..hh file contains a structure  definition  whose
       layout  parallels  that  of  the corresponding class. The fields in the
       structure correspond to instance variables in the class.

       The name of the header file and the structure declared  within  it  are
       derived  from  the  name  of the class. If the class passed to jjaavvaahh is
       inside a package, the package name is prepended to both the header file
       name  and the structure name. Underscores (  ) are used as name delim-
       iters.

       By default, jjaavvaahh creates a header file for each class  listed  on  the
       command  line  and  puts  the  files  in the current directory. Use the
       -ssttuubbss option to create source files. Use the -oo option to  concatenate
       the results for all listed classes into a single file.

       The  new native method interface, Java Native Interface (JNI), does not
       require header information or stub files.  The jjaavvaahh command can  still
       be  used  to generate native method function prototypes needed for JNI-
       style native methods.  jjaavvaahh produces JNI-style output by default,  and
       places the result in the ..hh file.

       The  jjaavvaahhgg  version  is a non-optimized version of jjaavvaahh suitable for
       use with debuggers like jjddbb.

OOPPTTIIOONNSS
       The following options are supported:

       -oo outputfile  Concatenates the resulting header or  source  files  for
                      all  the classes listed on the command line into oouuttppuutt-
                      ffiillee.  Only the -oo or -dd option may be used.

       -bboooottccllaassssppaatthh path
                      Specifies path from which to load bootstrap classes.  By
                      default,  the  bootstrap  classes are the classes imple-
                      menting  the   core   Java   2   platform   located   in
                      jjrree//lliibb//rrtt..jjaarr and several other jar files.

       -ccllaassssppaatthh path
                      Specifies  the path jjaavvaahh uses to look up classes. Over-
                      rides the default of the CCLLAASSSSPPAATTHH environment  variable
                      if  it is set. Directories are separated by colons. Thus
                      the general format for path is:

                           ..::<>

                      For example:

                           ..:://hhoommee//aavvhh//ccllaasssseess:://uussrr//llooccaall//jjaavvaa//ccllaasssseess


       -dd directory   Sets the directory where jjaavvaahh saves the header files or
                      the stub files.

       -ffoorrccee         Specifies that output files should always be written.

       -hheellpp          Prints help message for jjaavvaahh usage.

       -jjnnii           Causes  jjaavvaahh  to  create an output file containing JNI-
                      style native method function prototypes.   This  is  the
                      default output, so use of -jjnnii is optional.

       -oolldd           Specifies  the  old  JDK1.0-style header files should be
                      generated.

       -ssttuubbss         Causes jjaavvaahh to generate C declarations  from  the  Java
                      object file.

       -ttrraaccee         Tracing  is no longer supported.  Instead, use the -vveerr-
                      bboossee::jjnnii option of the virtual machine.

       -vveerrbboossee       Indicates verbose output and causes  jjaavvaahh  to  print  a
                      message to ssttddoouutt concerning the status of the generated
                      files.

       -vveerrssiioonn       Print out javah version information.

       -JJoption       Pass option to the Java virtual machine, where option is
                      one  of  the  options  described on the man page for the
                      java application launcher,  java(1).  For  example,  -JJ-
                      XXmmss4488mm  sets the startup memory to 48 megabytes. It is a
                      common convention for -JJ to pass options to the underly-
                      ing virtual machine.

ENVIRONMENT VARIABLES
       CCLLAASSSSPPAATTHH      Used  to  provide the system with a path to user-defined
                      classes.  Directories are separated by colons, for exam-
                      ple,

                 ..:://hhoommee//aavvhh//ccllaasssseess:://uussrr//llooccaall//jjaavvaa//ccllaasssseess

SEE ALSO
       jjaavvaa(1), jjaavvaacc(1), jjaavvaaddoocc(1), jjaavvaapp(1), jjddbb(1)



                                 13 June 2000                         javah(1)