GENASSYM.CF(5) OpenBSD Programmer's Manual GENASSYM.CF(5)
genassym.cf - assym.h definition file
The genassym.cf file is used by genassym.sh(8) to make constant C expres-
sions known to assembler source files.
Lines starting with '#' are discarded by genassym.sh(8). Lines starting
with include, ifdef, if, else or endif are preceded with '#' and passed
otherwise unmodified to the C compiler.
Lines starting with quote get passed on with the quote command removed.
The first word after a define command is taken as a CPP identifier and
the rest of the line has to be a constant C expression. The output of
genassym.sh(8) will assign the numerical value of this expression to the
is a shorthand for
define foo foo.
remembers foo for the member command and does a
define FOO_SIZEOF sizeof(foo),
with the structure name converted to upper case.
define FOO offsetof(<last struct>, foo).
The two argument form of member, as
member foo bar
define FOO offsetof(<last struct>, bar),
with its first argument converted to upper case. In the case where
struct was invoked with an extra argument, as in
struct foo PREFIX_,
the first argument of member will be prefixed by the remembered prefix,
before being converted to upper case.
is similar to the struct command, but applies to a union instead of a
config <ctype> <gcc constraint> <asm print modifier>
can be used to customize the output of genassym.sh(8).
When producing C output, values are cast to <ctype> (default: long) be-
fore they get handed to printf. <gcc constraint> (default: n) is the
constraint used in the __asm__ statements. <asm print modifier> (de-
fault: empty) can be used to force gcc to output operands in different
ways than normal. The "a" modifier e.g. stops gcc from emitting immedi-
ate prefixes in front of constants for the i386 and m68k port.
The first use of genassym.cf files occurred in OpenBSD 2.2. Its use was
generalized to all ports for OpenBSD 3.0. The union command appeared in
OpenBSD 3.6 April 25, 1998 1