AT&T UNIX™PC Unix System V Users Manual - tenox

SDB ( l ) SDB ( 1)
NAME
sdb - symbolic debugger
SYNOPSIS
sdb [-w] [-W] [ objfil [ corfil [ directory-list ] ] ]
DESCRIPTION
Sdb is a symbolic debugger that can be used with C programs. It
may be used to examine their object files and core files and to provide
a controlled environment for their execution.
Objfil is normally an executable program file which has been compiled
with the -g (debug) option; if it has not been compiled with
the -g option, or if it is not an executable file, the symbolic capabilities
of sdb will be limited, but the file can still be examined
and the program debugged. The default for objfil is a.out.
Corfil is assumed to be a core image file produced after executing
objfil ; the default for corfil is core. The core file need not be
present. A - in place of corfil will force sdb to ignore any core
image file. The colon separated list of directories (directories-list)
is used to locate the source files used to build objfil .
It is useful to know that at any time there is a current line and
current file . If corfil exists then they are initially set to the line
and file containing the source statement at which the process terminated.
Otherwise, they are set to the first line in main(). The
current line and file may be changed with the source file examination
commands.
Initially sdb has a greater-than character ( > ) prompt, which indicates
that sdb is ready for the user to enter the first command.
After sdb has begun, the prompt is < x >, where x is the name of
the last command given.
By default, warnings are provided if the source files used in producing
objfil cannot be found, or are newer than objfil . This
checking feature and the accompanying warnings may be disabled
by the use of the -W flag.
Names of variables are written just as they are in C. Note that
names in C are now of arbitrary length, sdb will no longer truncate
names. Variables local to a procedure may be accessed using
the form procedure :variable. If no procedure name is given, the
procedure containing the current line is used by default.
It is also possible to refer to structure members as
variable .member, pointers to structure members as
variable -> member and array elements as variable [number].
Pointers may be dereferenced by using the form pointer [0]. Combinations
of these forms may also be used. A number may be
used in place of a structure variable name, in which case the
number is viewed as the address of the structure, and the template
used for the structure is that of the last structure referenced
by sdb. An unqualified structure variable may also be used with
various commands. Generally, sdb will interpret a structure as a
set of variables. Thus, sdb will display the values of all the elements
of a structure when it is requested to display a structure.
- 1 -