GCJH(1) GNU GCJH(1)NAME
gcjh - - generate header files from Java class files
SYNOPSIS
gcjh [OPTIONS]... CLASS...
DESCRIPTION
The "gcjh" program is used to generate header files from class files. It can generate both CNI and JNI header files, as well as stub
implementation files which can be used as a basis for implementing the required native methods. It is similar to "javah" but has slightly
different command line options, and defaults to CNI.
OPTIONS
See "javah" for a full description; this page only lists the additional options provided by "gcjh".
CNI text options
-add text
Insert text into class body.
-append text
Append text after class declaration.
-friend text
Insert text as a "friend" declaration.
-prepend text
Insert text before start of class.
Compatibility options (unused)
-td DIR
-M
-MM
-MD
-MMD
Unused compatibility option.
Standard options:
-help
Print help text, then exit.
-version
Print version number, then exit.
-JOPTION
Pass argument to the Java runtime.
BUGS SEE ALSO javac(1), javah(1), ...
AUTHOR 0.98 2010-07-05 GCJH(1)
Check Out this Related Man Page
javah(1) General Commands Manual javah(1)NAME
javah - C header and stub file generator
SYNOPSIS
javah [ options ] fully-qualified-classname ...
javah_g [ options ] fully-qualified-classname ...
DESCRIPTION
The 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 .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.
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 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.
By default, javah creates a header file for each class listed on the command line and puts the files in the current directory. Use the
-stubs option to create source files. Use the -o 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 javah command can
still be used to generate native method function prototypes needed for JNI-style native methods. javah produces JNI-style output by
default, and places the result in the .h file.
The javah_g version is a non-optimized version of javah suitable for use with debuggers like jdb.
OPTIONS
The following options are supported:
-o outputfile Concatenates the resulting header or source files for all the classes listed on the command line into outputfile. Only the
-o or -d option may be used.
-bootclasspath path
Specifies path from which to load bootstrap classes. By default, the bootstrap classes are the classes implementing the
core Java 2 platform located in jre/lib/rt.jar and several other jar files.
-classpath path
Specifies the path javah uses to look up classes. Overrides the default of the CLASSPATH environment variable if it is set.
Directories are separated by colons. Thus the general format for path is:
.:<your_path>
For example:
.:/home/avh/classes:/usr/local/java/classes
-d directory Sets the directory where javah saves the header files or the stub files.
-force Specifies that output files should always be written.
-help Prints help message for javah usage.
-jni Causes javah to create an output file containing JNI-style native method function prototypes. This is the default output,
so use of -jni is optional.
-old Specifies the old JDK1.0-style header files should be generated.
-stubs Causes javah to generate C declarations from the Java object file.
-trace Tracing is no longer supported. Instead, use the -verbose:jni option of the virtual machine.
-verbose Indicates verbose output and causes javah to print a message to stdout concerning the status of the generated files.
-version Print out javah version information.
-Joption Pass option to the Java virtual machine, where option is one of the options described on the man page for the java applica-
tion launcher, java(1). For example, -J-Xms48m sets the startup memory to 48 megabytes. It is a common convention for -J to
pass options to the underlying virtual machine.
ENVIRONMENT VARIABLES
CLASSPATH Used to provide the system with a path to user-defined classes. Directories are separated by colons, for example,
.:/home/avh/classes:/usr/local/java/classes
SEE ALSO java(1), javac(1), javadoc(1), javap(1), jdb(1)
13 June 2000 javah(1)