sccs.me

早期freebsd实现

that you don't want to lose.
The commands:
.(b
sccs edit \-i1.5.1.1\-1.5.1 prog.c
sccs delta prog.c
.)b
will merge all of your changes
into the release system.
If some of the changes conflict,
get will print an error;
the generated result
should be carefully examined
before the delta is made.
.sh 2 "A more detailed example"
.pp
The following technique might be used
to maintain a different version of a program.
First,
create a directory to contain the new version:
.(b
mkdir ../newxyz
cd ../newxyz
.)b
Edit a copy of the program
on a branch:
.(b
sccs \-d../xyz edit prog.c
.)b
When using the old version,
be sure to use the
.b \-b
flag to info, check, tell, and clean
to avoid confusion.
For example, use:
.(b
sccs info \-b
.)b
when in the directory
.q xyz .
.pp
If you want to save a copy of the program
(still on the branch)
back in the s-file,
you can use:
.(b
sccs -d../xyz deledit prog.c
.)b
which will do a delta on the branch
and reedit it for you.
.pp
When the experiment is complete, merge it back into the s-file
using delta:
.(b
sccs -d../xyz delta prog.c
.)b
At this point you must decide whether this version
should be merged back into the trunk
(\c
.i i.e.
the default version),
which may have undergone changes.
If so, it can be merged using the
.b \-i
flag to
.i edit
as described above.
.sh 2 "A warning"
.pp
Branches should be kept to a minimum.
After the first branch from the trunk,
\*I's are assigned rather haphazardly,
and the structure gets complex fast.
.sh 1 "Using \*S with Make"
.pp
\*S and make can be made to work together
with a little care.
A few sample makefiles
for common applications are shown.
.pp
There are a few basic entries that every makefile
ought to have.
These are:
.nr ii 1i
.ip a.out
(or whatever the makefile generates.)
This entry regenerates whatever this makefile is
supposed to regenerate.
If the makefile regenerates many things,
this should be called
.q all
and should in turn
have dependencies on everything
the makefile can generate.
.ip install
Moves the objects to the final
resting place,
doing any special
.i chmod 's
or
.i ranlib 's
as appropriate.
.ip sources
Creates all the source files from \*S files.
.ip clean
Removes all files from the current directory
that can be regenerated from \*S files.
.ip print
Prints the contents of the directory.
.lp
The examples shown below are only partial examples,
and may omit some of these entries
when they are deemed to be obvious.
.pp
The
.i clean
entry should not remove files that can be
regenerated from the \*S files.
It is sufficiently important to have the
source files around at all times
that the only time they should be removed
is when the directory is being mothballed.
To do this, the command:
.(b
sccs clean
.)b
can be used.
This will remove all files for which an s-file
exists,
but which is not being edited.
.sh 2 "To maintain single programs"
.pp
Frequently there are directories with several
largely unrelated programs
(such as simple commands).
These can be put into a single makefile:
.(b
LDFLAGS= \-i \-s
.sp \n(psu
prog: prog.o
	$(CC) $(LDFLAGS) \-o prog prog.o
prog.o: prog.c prog.h
.sp \n(psu
example: example.o
	$(CC) $(LDFLAGS) \-o example example.o
example.o: example.c
.sp \n(psu
\&.DEFAULT:
	sccs get $<
.)b
The trick here
is that the .DEFAULT rule
is called every time
something is needed
that does not exist,
and no other rule exists to make it.
The explicit dependency of the
.b \&.o
file on the
.b \&.c
file is important.
Another way of doing the same thing is:
.(b
SRCS=	prog.c prog.h example.c
.sp \n(psu
LDFLAGS= \-i \-s
.sp \n(psu
prog: prog.o
	$(CC) $(LDFLAGS) \-o prog prog.o
prog.o: prog.h
.sp \n(psu
example: example.o
	$(CC) $(LDFLAGS) \-o example example.o
.sp \n(psu
sources: $(SRCS)
$(SRCS):
	sccs get $@
.)b
There are a couple of advantages to this approach:
(1) the explicit dependencies of the .o on the .c files are
not needed,
(2) there is an entry called "sources" so if you want to get
all the sources you can just say
.q "make sources" ,
and
(3) the makefile is less likely to do confusing things
since it won't try to
.i get
things that do not exist.
.sh 2 "To maintain a library"
.pp
Libraries that are largely static
are best updated using explicit commands,
since
.i make
doesn't know about updating them properly.
However,
libraries that are in the process of being developed
can be handled quite adequately.
The problem is that the .o files
have to be kept out of the library
as well as in the library.
.(b
# configuration information
OBJS=	a.o b.o c.o d.o
SRCS=	a.c b.c c.c d.s x.h y.h z.h
TARG=	/usr/lib
.sp \n(psu
# programs
GET=	sccs get
REL=
AR=	\-ar
RANLIB=	ranlib
.sp \n(psu
lib.a: $(OBJS)
	$(AR) rvu lib.a $(OBJS)
	$(RANLIB) lib.a
.sp \n(psu
install: lib.a
	sccs check
	cp lib.a $(TARG)/lib.a
	$(RANLIB) $(TARG)/lib.a
.sp \n(psu
sources: $(SRCS)
$(SRCS):
	$(GET) $(REL) $@
.sp \n(psu
print: sources
	pr *.h *.[cs]
clean:
	rm \-f *.o
	rm \-f core a.out $(LIB)
.)b
.pp
The
.q "$(REL)"
in the get
can be used to get old versions
easily; for example:
.(b
make b.o REL=\-r1.3
.)b
.pp
The
.i install
entry includes the line
.q "sccs check"
before anything else.
This guarantees that all the s-files
are up to date
(\c
.i i.e. ,
nothing is being edited),
and will abort the
.i make
if this condition is not met.
.sh 2 "To maintain a large program"
.(b
OBJS=	a.o b.o c.o d.o
SRCS=	a.c b.c c.y d.s x.h y.h z.h
.sp \n(psu
GET=	sccs get
REL=
.sp \n(psu
a.out: $(OBJS)
	$(CC) $(LDFLAGS) $(OBJS) $(LIBS)
.sp \n(psu
sources: $(SRCS)
$(SRCS):
	$(GET) $(REL) $@
.)b
(The
.i print
and
.i clean
entries are identical to the previous case.)
This makefile requires copies of the source and object files
to be kept during development.
It is probably also wise to include lines of the form:
.(b
a.o: x.h y.h
b.o: z.h
c.o: x.h y.h z.h
z.h: x.h
.)b
so that modules will be recompiled
if header files change.
.pp
Since
.i make
does not do transitive closure on dependencies,
you may find in some makefiles lines like:
.(b
z.h: x.h
	touch z.h
.)b
This would be used in cases where file z.h
has a line:
.(b
#include "x.h"
.)b
in order to bring the mod date of z.h in line
with the mod date of x.h.
When you have a makefile such as above,
the
.i touch
command can be removed completely;
the equivalent effect will be achieved
by doing an automatic
.i get
on z.h.
.sh 1 "Further Information"
.pp
The
.i "SCCS/PWB User's Manual"
gives a deeper description
of how to use \*S.
Of particular interest
are the numbering of branches,
the l-file,
which gives a description of what deltas were used on a get,
and certain other \*S commands.
.pp
The \*S manual pages
are a good last resort.
These should be read by software managers
and by people who want to know
everything about everything.
.pp
Both of these documents were written without the
.i sccs
front end in mind,
so most of the examples are slightly different from those
in this document.
.bp
.sz 12
.ce
.b "Quick Reference"
.sz
.sp 2
.sh 1 Commands 1
.pp
The following commands should all be preceded with
.q sccs .
This list is not exhaustive;
for more options see
.i "Further Information" .
.ip get 9n
Gets files for compilation (not for editing).
Id keywords are expanded.
.ba 9n
.nr ii 8n
.ip \-r\fI\*I\fP
Version to get.
.ip \-p
Send to standard output rather than to the actual file.
.ip \-k
Don't expand id keywords.
.ip \-i\fIlist\fP
List of deltas to include.
.ip \-x\fIlist\fP
List of deltas to exclude.
.ip \-m
Precede each line with \*I of creating delta.
.ip \-c\fIdate\fP
Don't apply any deltas created after
.i date.
.ba
.ip edit 9n
Gets files for editing.
Id keywords are not expanded.
Should be matched with a
.i delta
command.
.ba 9n
.nr ii 8n
.ip \-r\fI\*I\fP
Same as
.i get .
If
.i \*I
specifies a release that does not yet exist,
the highest numbered delta is retrieved
and the new delta is numbered with
.i \*I .
.ip \-b
Create a branch.
.ip \-i\fIlist\fP
Same as
.i get .
.ip \-x\fIlist\fP
Same as
.i get .
.ba
.ip delta 9n
Merge a file gotten using
.i edit
back into the s-file.
Collect comments about why this delta was made.
.ip unedit 9n
Remove a file that has been edited previously
without merging the changes into the s-file.
.ip prt 9n
Produce a report of changes.
.ba 9n
.nr ii 5n
.ip \-t
Print the descriptive text.
.ip \-e
Print (nearly) everything.
.ba
.ip info 9n
Give a list of all files being edited.
.ba 9n
.nr ii 5n
.ip \-b
Ignore branches.
.ip \-u[\fIuser\fP]
Ignore files not being edited by
.i user .
.ba
.ip check 9n
Same as
.i info ,
except that nothing is printed if nothing is being edited
and exit status is returned.
.ip tell 9n
Same as
.i info ,
except that one line is produced per file being edited containing
only the file name.
.ip clean 9n
Remove all files that can be regenerated from the
s-file.
.ip what 9n
Find and print id keywords.
.ip admin 9n
Create or set parameters on s-files.
.ba 9n
.nr ii 8n
.ip \-i\fIfile\fP
Create, using
.i file
as the initial contents.
.ip \-z
Rebuild the checksum in case
the file has been trashed.
.ip \-f\fIflag\fP
Turn on the
.i flag .
.ip \-d\fIflag\fP
Turn off (delete) the
.i flag .
.ip \-t\fIfile\fP
Replace the descriptive text
in the s-file with the contents of
.i file .
If
.i file
is omitted,
the text is deleted.
Useful for storing documentation
or
.q "design & implementation"
documents to insure they get distributed with the
s-file.
.lp
Useful flags are:
.ip b
Allow branches to be made using the \-b flag to
.i edit.
.ip d\fI\*I\fP
Default \*I to be used
on a
.i get
or
.i edit .
.ip i
Cause
.q "No Id Keywords"
error message
to be a fatal error rather than a warning.
.ip t
The module
.q type ;
the value of this flag replaces the
.b %\&Y\&%
keyword.
.ba
.ip fix 9n
Remove a delta and reedit it.
.ip delget 9n
Do a
.i delta
followed by a
.i get .
.ip deledit 9n
Do a
.i delta
followed by an
.i edit .
.sh 1 "Id Keywords"
.nr ii 6n
.ip "%\&Z\&%"
Expands to
.q @\&(#)
for the
.i what
command to find.
.ip "%\&M\&%"
The current module name,
.i e.g.,
.q prog.c .
.ip "%\&I\&%"
The highest \*I applied.
.ip "%\&W\&%"
A shorthand for
.q "%\&Z\&%%\&M\&% <tab> %\&I\&%" .
.ip "%\&G\&%"
The date of the delta
corresponding to the
.q "%\&I\&%"
keyword.
.ip "%\&R\&%"
The current release number,
.i i.e. ,
the first component of the
.q "%\&I\&%"
keyword.
.ip "%\&Y\&%"
Replaced by the value of the
.b t
flag
(set by
.i admin ).