Updated: 2021/Apr/14

GENASSYM(1)                 General Commands Manual                GENASSYM(1)

     genassym - emit an assym.h file

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

     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 constants
     derived from the configuration information genassym reads from stdin. The
     generated file is used by kernel sources written in assembler 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.

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


     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.

NetBSD 9.99                     April 13, 2010                     NetBSD 9.99