'\" t
.\" @(#)javah.1 1.7 99/02/19 SMI;
.\" Copyright 1999 Sun Microsystems, Inc. All rights reserved.
.\" Copyright 1999 Sun Microsystems, Inc. Tous droits réservés.
.\" 
'\"macro stdmacro
.TH javah 1 "18 Feb 1999"
.SH NAME
javah \- C header and stub file generator
.\" 
.\"  This document was created by saving an HTML file as text
.\"  from the JavaSoft web site:
.\" 
.\" http://java.sun.com/products/jdk/1.2/docs/tooldocs/tools.html
.\" 
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.\"  man pages can change without notice, it may be helpful to diff
.\"  files to identify changes other than new functionality. 
.\" 
.SH SYNOPSIS
.B javah 
[
.B options
]
.I fully-qualified-classname . . .
.br
.B javah_g 
[
.B options
]
.I fully-qualified-classname . . .
.SH DESCRIPTION
.IX "stub file generator" "" "stub file generator \(em \fLjavah\fP"
.IX "C header and stub file generator" "" "C header and stub file generator \(em \fLjavah\fP"
.IX "javah" "" "\fLjavah\fP \(em C header and stub file generator"
The
.B javah 
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 
.B .h 
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.
.LP
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
.B javah 
is inside a package, the package name is prepended to both
the header file name and the structure name. Underscores ( _ ) are
used as name delimiters.
.LP
By default,
.B javah 
creates a header file for each class listed on
the command line and puts the files in the current directory. Use
the 
.B  \-stubs 
option to create source files. Use the 
.B  \-o 
option to
concatenate the results for all listed classes into a single file.
.LP
The new native method interface, Java\(tm Native Interface (JNI), does
not require header information or stub files. 
The
.B javah 
command can still be
used 
to generate native method function prototypes needed for
JNI-style native methods.
.B javah 
produces JNI-style output by default, and places the result in the
.B .h
file.
.LP
The
.B javah_g 
version is a non-optimized version of 
.B javah 
suitable for use with
debuggers like 
.BR jdb .
.SH OPTIONS
The following options are supported:
.TP 15
.BI \-bootclasspath " path"
Specifies path from which to load bootstrap classes.
By default, the bootstrap classes are the classes
implementing the core Java platform located in
.B jre/lib/rt.jar
and 
.BR jre/lib/i18n.jar .
.TP 15
.BI \-classpath " path"
Specifies the path 
.B javah 
uses to look up classes. Overrides
the default of the 
.SB CLASSPATH 
environment variable if it is
set. Directories are separated by colons. Thus the general
format for path is:
.RS 20
.sp 1n
.B .:<your_path>
.sp 1n
.RE
.RS 15
For example:
.RE
.RS 20
.sp 1n
.B .:/home/avh/classes:/usr/local/java/classes
.sp 1n
.RE
.TP 15
.BI \-d " directory"
Sets the directory where 
.B javah 
saves the header files or the
stub files.
.TP 15
.B  \-force
Specifies that output files should always be written.
.TP 15
.B  \-help
Prints help message for 
.B javah
usage.
.TP 15
.B  \-jni
Causes 
.B javah 
to create an output file containing JNI-style
native method function prototypes.
This is the default output so use of
-B \-jni
is optional.
.TP 15
.BI \-o " outputfile"
Concatenates the resulting header or source files for all the
classes listed on the command line into 
.BR outputfile .
Only the
.B \-o
or
.B \-d
option may be used.
.TP 15
.B \-old
Specifies the old JDK1.0-style header files should be
generated.
.TP 15
.B \-stubs
Causes 
.B javah 
to generate C declarations from the Java object
file.
Only the
.B \-o
or
.B \-d
option may be used.
.TP 15
.B  \-trace
Adds tracing information to the stubs file.
.TP 15
.B \-verbose
Indicates verbose output and causes 
.B javah 
to print a message
to 
.B stdout 
concerning the status of the generated files.
.TP 15
.B  \-version
Prints build version.
.SH ENVIRONMENT VARIABLES
.TP 15
.SB CLASSPATH
Used to provide the system with a path to user-defined classes.
Directories are separated by colons, for example,
.RS 20
.sp 1n
.B .:/home/avh/classes:/usr/local/java/classes
.RE
.SH ATTRIBUTES
See
.BR attributes (5)
for a description of the following attributes:
.sp
.TS
box;
cbp-1 | cbp-1
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
=
Availability	SUNWjvdev
.TE
.SH SEE ALSO
.BR  java (1),
.BR  javac (1),
.BR  javadoc (1),
.BR  javap (1),
.BR  jdb (1),
.BR attributes (5)