term% cat index.txt SDB(1) General Commands Manual SDB(1)
NAME
sdb - symbolic debugger
SYNOPSIS
sdb [ objfil [ corfil [ directory ] ] ]
DESCRIPTION
Sdb is a symbolic debugger. It may examine source and/or object files
and provide a controlled environment for execution.
Objfil is an executable program file which has been compiled with the
-g (debug) option of cc, pascal, or f77(1). The default for objfil is
a.out. Corfil is assumed to be a core image file produced after exe‐
cuting objfil; the default for corfil is core. Directory names the lo‐
cation of source files, by default the current directory.
Sdb maintains a current line and a current file. If corfil exists then
they are initially set to the line and file containing the source
statement at which the process terminated or stopped. Otherwise, they
are set to the first line in function main.
Names of variables are written just as they are in C, Pascal, or For‐
tran. 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. A member of a struc‐
ture may be referred to as `variable.member' or `variable->member'; an
array element as `variable[number]'. Combinations of these forms may
be used.
It is also possible to specify a variable by address. All forms of in‐
teger constants which are valid in C may be used.
Line numbers in the source program are referred to as `filename:number'
or `procedure:number'. In either case the number is relative to the
beginning of the file. If no procedure or file name is given, the cur‐
rent file is used by default. If no number is given, the first line of
the named procedure or file is used.
The commands for examining data are:
t Print a stack trace of the terminated or stopped program.
T Print the top line of the stack trace.
variable/lm
Print the value of variable according to length l and format m.
If l and m are omitted, sdb chooses a length and format suitable
for the variable's type as declared in the program. The length
specifiers are:
b one byte
h two bytes (half word)
l four bytes (long word)
number string length for formats s and a
Legal values for m are:
c character
d decimal
u decimal, unsigned
o octal
x hexadecimal
f 32 bit single precision floating point
g 64 bit double precision floating point
s Assume variable is a string pointer and print characters
until a null is reached.
a Print characters starting at the variable's address until a
null is reached.
p pointer to procedure
The length specifiers are only effective with the formats d, u, o
and x. If one of these formats is specified and l is omitted, the
length defaults to the word length of the host machine: 4 for the
VAX. The last variable may be redisplayed with the command `./'.
The sh(1) metacharacters * and ? may be used within procedure and
variable names, providing a limited form of pattern matching. If
no procedure name is given, both variables local to the current
procedure and global (common for f77) variables are matched. If a
procedure name is specified, only variables local to that proce‐
dure are matched. The form `:pattern' matches only global vari‐
ables (blank common for f77),. The name of a common block may be
specified instead of a procedure name for f77 programs.
variable=lm
linenumber=lm
number=lm
Print the address of the variable or line number or the value of
the number in the specified format. If no format is given, then
`lx' is used. The last variant of this command provides a conve‐
nient way to convert between decimal, octal and hexadecimal.
variable!value
Set the variable to the given value. The value may be a number,
character constant or a variable. If the variable is of type
float or double, the value may also be a floating constant.
The commands for examining source files are
e procedure
e filename.c
Set the current file to the file containing the named procedure or
the named filename. Set the current line to the first line in the
named procedure or file. If no procedure or file name is given,
the current procedure and file names are reported.
/regular expression/
Search forward from the current line for a line containing a
string matching the regular expression as in ed(1). The trailing
`/' may be elided.
?regular expression?
Search backward from the current line for a line containing a
string matching the regular expression as in ed(1). The trailing
`?' may be elided.
p Print the current line.
z Print the current line followed by the next 9 lines. Set the cur‐
rent line to the last line printed.
control-D
Scroll. Print the next 10 lines. Set the current line to the
last line printed.
w Window. Print the 10 lines around the current line.
number
Set the current line to the given line number. Print the new cur‐
rent line.
count +
Advance the current line by count lines. Print the new current
line.
count −
Retreat the current line by count lines. Print the new current
line.
The commands for controlling the execution of the source program are:
count r args
count R
Run the program with the given arguments. The r command with no
arguments reuses the previous arguments to the program while the R
command runs the program with no arguments. An argument beginning
with `<' or `>' causes redirection for the standard input or out‐
put respectively. If count is given, it specifies the number of
breakpoints to be ignored.
linenumber c count
linenumber C count
Continue after a breakpoint or interrupt. If count is given, it
specifies the number of breakpoints to be ignored. C continues
with the signal which caused the program to stop and c ignores it.
If a linenumber is given then a temporary breakpoint is placed at
the line and execution is continued. The breakpoint is deleted
when the command finishes.
count s
Single step. Run the program through count lines. If no count is
given then the program is run for one line.
count S
Single step, but step through subroutine calls.
k Kill the debugged program.
procedure(arg1,arg2,...)
procedure(arg1,arg2,...)/m
Execute the named procedure with the given arguments. Arguments
can be integer, character or string constants or names of vari‐
ables accessible from the current procedure. The second form
causes the value returned by the procedure to be printed according
to format m. If no format is given, it defaults to `d'.
linenumber b commands
Set a breakpoint at the given line. If a procedure name without a
line number is given (e.g. `proc:'), a breakpoint is placed at the
first line in the procedure even if it was not compiled with the
debug flag. If no linenumber is given, a breakpoint is placed at
the current line.
If no commands are given then execution stops just before the
breakpoint and control is returned to sdb. Otherwise the semi‐
colon-separated commands are executed when the breakpoint is en‐
countered and execution continues.
linenumber d
Delete a breakpoint at the given line. If no linenumber is given,
each breakpoint location is printed and a line is read from the
standard input. If the line begins with a `y' or `d' then the
breakpoint is deleted.
B Print a list of the currently active breakpoints.
D Delete all breakpoints.
l Print the last executed line.
linenumber a
Announce. If linenumber is of the form `proc:number', the command
does a `linenumber b l'. If linenumber is of the form `proc:',
the command does a `proc: b T'.
Miscellaneous commands.
! command
The command is interpreted by sh(1).
newline
If the previous command printed a source line then advance the
current line by 1 line and print the new current line. If the
previous command displayed a core location then display the next
core location.
" string
Print the given string.
q Exit the debugger.
The following commands are intended for debugging the debugger.
V Print the version number.
X Print a list of procedures and files being debugged.
Y Toggle debug output.
FILES
a.out
core
DIAGNOSTICS
Error reports are either identical to those of adb(1) or are self-ex‐
planatory.
SEE ALSO
adb(1), pi(9.1), coreid(1)
BUGS
If a procedure is called when the program is not stopped at a break‐
point (such as when a core image is being debugged), all variables are
initialized before the procedure is started. This makes it impossible
to use a procedure to extract data from a core image.
Arrays must be of one dimension and of zero origin to be correctly ad‐
dressed.
The default type for printing Fortran parameters is incorrect: address
instead of value.
Tracebacks containing Fortran subprograms with multiple entry points
may print too many arguments in the wrong order, but their values are
correct.
Sdb understands Pascal, but not its types.
The meaning of control-D is nonstandard
SDB(1)