NAME
genassym.sh —
emit an assym.h file
SYNOPSIS
sh genassym.sh |
[-c] C compiler
invocation |
DESCRIPTION
genassym.sh 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.sh 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.
genassym.sh resides in the
/sys/kern directory. Arguments to
genassym.sh 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.sh 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.sh 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.
DIAGNOSTICS
Either self-explanatory, or generated by one of the programs
called from the script. The script will exit with the return code from the
compiler or, in the -c case, with the return code
from the generated executable.
SEE ALSO
HISTORY
The genassym.sh script first appeared in
OpenBSD 2.2.