GENASSYM(1)						    BSD General Commands Manual 					       GENASSYM(1)

NAME

     genassym -- emit an assym.h file

SYNOPSIS

     genassym [-c] [-f] C compiler invocation

DESCRIPTION

     genassym is a shell script normally used during the kernel build process to create an assym.h file.  This file defines a number of cpp con-
     stants derived from the configuration information genassym reads from stdin. The generated file is used by kernel sources written in assem-
     bler to gain access to information (e.g. structure offsets and sizes) normally only known to the C compiler.

     Arguments to genassym are usually of the form ${CC} ${CFLAGS} ${CPPFLAGS} where ${CC} is the C compiler used to compile the kernel, while
     ${CFLAGS} and ${CPPFLAGS} are flag arguments to the C compiler. The script creates a C source file from its input. Then the C compiler is
     called according to the script's arguments to compile this file.

     Normally genassym instructs the C compiler to create an assembler source from the constructed C source. The resulting file is then processed
     to extract the information needed to create the assym.h file. The -c flag instructs genassym to create slightly different code, generate an
     executable from this code and run it. In both cases the assym.h file is written to stdout.  The -f flag instructs genassym to create forth
     code.

DIAGNOSTICS

     Either self-explanatory, or generated by one of the programs called from the script.

SEE ALSO

     genassym.cf(5)

HISTORY

     The genassym command appeared in NetBSD 1.3 as ``genassym.sh'' in /usr/src/sys/kern.  It became a userland utility in NetBSD 4.0.

BSD
								  April 13, 2010							       BSD