With the advent of Autoconf, it's rarely necessary to have host definition machinery anymore. The following information is provided, mainly, as an historical reference.
gdb's host configuration support normally happens via Autoconf. New host-specific definitions should not be needed. Older hosts gdb still use the host-specific definitions and files listed below, but these mostly exist for historical reasons, and will eventually disappear.
Host configuration information included definitions for
XM_CDEPS, etc.; see Makefile.in.
New host-only configurations do not need this file.
(Files named gdb/config/arch/xm-xyz.h were once used to define host-specific macros, but were no longer needed and have all been removed.)
There are some “generic” versions of routines that can be used by various systems.
When gdb is configured and compiled, various macros are
defined or left undefined, to control compilation based on the
attributes of the host system. While formerly they could be set in
host-specific header files, at present they can be changed only by
CFLAGS when building, or by editing the source code.
These macros and their meanings (or if the meaning is not documented here, then one of the source files where they are used is indicated) are:
\nas a line terminator. This will cause source file listings to omit
\rcharacters when printing and it will allow
\r\nline endings of files which are “sourced” by gdb. It must be possible to open files in binary mode using
O_BINARYor, for fopen,
ll. This is set by the
lseek (n)does not necessarily move to byte number
nin the file. This is only used when reading source files. It is normally faster to define
lintin some situations.