dvadura@watdragon.waterloo.edu (Dennis Vadura) (10/15/90)
Posting-number: Volume 15, Issue 64
Submitted-by: Dennis Vadura <dvadura@watdragon.waterloo.edu>
Archive-name: dmake-3.6/part12
#!/bin/sh
# this is part 12 of a multipart archive
# do not concatenate these parts, unpack them in order with /bin/sh
# file man/dmake.tf continued
#
CurArch=12
if test ! -r s2_seq_.tmp
then echo "Please unpack part 1 first!"
exit 1; fi
( read Scheck
if test "$Scheck" != $CurArch
then echo "Please unpack part $Scheck next!"
exit 1;
else exit 0; fi
) < s2_seq_.tmp || exit 1
echo "x - Continuing file man/dmake.tf"
sed 's/^X//' << 'SHAR_EOF' >> man/dmake.tf
Xto introduce options on command lines. On UNIX it's value is '-', on
XMSDOS it's value may be '/' or '-'.
XThe macro is internally defined and is not user setable.
XThe MSDOS version of \fBdmake\fP attempts to first extract SWITCHAR from an
Xenvironment variable of the same name. If that fails it then attempts to
Xuse the undocumented getswitchar interrupt call, and returns the result of
Xthat. Thus under MSDOS version 4.0 you must set the value of the environment
Xmacro SWITCHAR to '/' to obtain predictable behaviour.
X.PP
XAll boolean macros currently understood by
X.B dmake
Xcorrespond directly to the previously defined attributes.
XThese macros provide
Xa second way to apply global attributes, and represent the
Xpreferred method of doing so. They are used by assigning them a
Xvalue. If the value is not a NULL string then the boolean condition
Xis set to on.
XIf the value is a NULL string then the condition is set to off.
XThere are five conditions defined and they correspond directly to the
Xattributes of the same name. Their meanings are defined in the ATTRIBUTES
Xsection above.
XThe macros are:
X\&\fB.EPILOG\fP,
X\&\fB.IGNORE\fP,
X\&\fB.MKSARGS\fP,
X\&\fB.PRECIOUS\fP,
X\&\fB.PROLOG\fP,
X\&\fB.SEQUENTIAL\fP,
X\&\fB.SILENT\fP,
X\&\fB.SWAP\fP, and
X\&\fB.USESHELL\fP.
XAssigning any of these a non NULL value will globally set
Xthe corresponding attribute to on.
X.SH "RUN_TIME MACROS"
XThese macros are defined
Xwhen \fBdmake\fP is making targets, and may take on different values for each
Xtarget. \fB$@\fP is defined to be the full target name, \fB$?\fP is the
Xlist of all out of date prerequisites, \fB$&\fP is the list of all
Xprerequisites, \fB$>\fP is the name of the library if the current target is a
Xlibrary member, and
X\fB$<\fP is the list of prerequisites specified in the current rule.
XIf the current target had a recipe inferred then \fB$<\fP is the name of the
Xinferred prerequisite even if the target had a list of prerequisites supplied
Xusing an explicit rule that did not provide a recipe. In such situations
X\fB$&\fP gives the full list of prerequisites.
X.PP
X\fB$*\fP is defined as
X\fB$(@:db)\fP when making targets with explicit recipes and is defined as the
Xvalue of % when making targets whose recipe is the result of an inference.
XIn the first case \fB$*\fP is the target name with no suffix,
Xand in the second case, is the value of the matched % pattern from
Xthe associated %-rule.
X\fB$^\fP expands to the set of out of date prerequisites taken from the
Xcurrent value of \fB$<\fP.
XIn addition to these,
X\fB$$\fP expands to $, \fB{{\fP expands to {, \fB}}\fP expands to }, and the
Xstrings \fB<+\fP and \fB+>\fP are recognized
Xas respectively starting and terminating a text diversion when they appear
Xliterally together in the same input line.
X.PP
XThe difference between $? and $^ can best be illustrated by an example,
Xconsider:
X.RS
X.sp
X.nf
Xfred.out : joe amy hello
X\trules for making fred
X
Xfred.out : my.c your.h his.h her.h # more prerequisites
X.fi
X.sp
X.RE
XAssume joe, amy, and my.c are newer then fred.out. When
X.B dmake
Xexecutes the recipe for making fred.out the values of the following macros
Xwill be:
X.RS
X.sp
X.nf
X.Is "$@ "
X.Ii "$@"
X--> fred.out
X.Ii "$*"
X--> fred
X.Ii "$?"
X--> joe amy my.c # note the difference between $? and $^
X.Ii "$^"
X--> joe amy
X.Ii "$<"
X--> joe amy hello
X.Ii "$&"
X--> joe amy hello my.c your.h his.h her.h
X.fi
X.sp
X.RE
X.SH "FUNCTION MACROS"
XOnly one function macro is defined at this time. The $(mktmp ...) construct
Xcan be used to create a temporary file containing data and returns the name
Xof that file as it's result. See the TEXT DIVERSION section for details on
Xits use. Temporary files created using this macro persist for the duration
Xof the
X.B dmake
Xrun if processed as part of a macro assignment operation, or until an
Xassociated target's recipe is fully completed at which time the temporary file
Xis removed. NOTE: Specifying '-v' on the command line causes all temporary
Xfiles to be retained when
X.B dmake
Xexits.
X.SH "DYNAMIC PREREQUISITES"
X.B dmake
Xlooks for prerequisites whose names contain macro expansions during target
Xprocessing. Any such prerequisites are expanded and the result of the
Xexpansion is used as the prerequisite name. As an example the line:
X.sp
X\tfred : $$@.c
X.sp
Xcauses the $$@ to be expanded when \fBdmake\fP is making fred, and it resolves
Xto the target \fIfred\fP.
XThis enables dynamic prerequisites to be generated. The value
Xof @ may be modified by any of the valid macro modifiers. So you can say for
Xexample:
X.sp
X\tfred.out : $$(@:b).c
X.sp
Xwhere the $$(@:b) expands to \fIfred\fP.
XNote the use of $$ instead of $ to indicate the dynamic expansion, this
Xis due to the fact that the rule line is expanded when it is initially parsed,
Xand $$ then returns $ which later triggers the dynamic prerequisite expansion.
XIf you really want a $ to be part of a prerequisite name you must use $$$$.
XDynamic macro expansion is performed in all user defined rules,
Xand the special targets .SOURCE*, and .INCLUDEDIRS.
X.SH "BINDING TARGETS"
XThis operation takes a target name and binds it to an existing file, if
Xpossible.
X.B dmake
Xmakes a distinction between the internal target name of a target and it's
Xassociated external file name.
XThus it is possible for a target's internal name and its external
Xfile name to differ.
XTo perform the binding, the following set of rules is used.
XAssume that we are
Xtrying to bind a target whose name is of the form \fIX.suff\fP,
Xwhere \fI.suff\fP is the suffix and \fIX\fP is the stem portion
X(ie. that part which contains the directory and the basename).
X.B dmake
Xtakes this target name and performs a series of search operations that try to
Xfind a suitably named file in the external file system.
XThe search operation is user controlled
Xvia the settings of the various .SOURCE targets.
X.RS
X.IP 1.
XIf target has the .SYMBOL attribute set then look for it in the library.
XIf found, replace the target name with the library member name and continue
Xwith step 2. If the name is not found then return.
X.IP 2.
XExtract the suffix portion (that following the `.') of the target name.
XIf the suffix is not null, look up the special target .SOURCE.<suff>
X(<suff> is the suffix).
XIf the special target exists then search each directory given in
Xthe .SOURCE.<suff> prerequisite list for the target.
XIf the target's suffix was null (ie. \fI.suff\fP was empty) then
Xperform the above search but use the special target .SOURCE.NULL instead.
XIf at any point a match is found then terminate the search.
XIf a directory in the prerequisite list is the special name `.NULL ' perform
Xa search for the full target name without prepending any directory portion
X(ie. prepend the NULL directory).
X(a default target of '.SOURCE : .NULL' is defined by \fBdmake\fP at startup,
Xand is user redefinable)
X.IP 3.
XThe search in step 2. failed. Repeat the same search but this time
Xuse the special target .SOURCE.
X.IP 4.
XThe search in step 3. failed.
XIf the target has the library member attribute (.LIBMEMBER)
Xset then try to find the target in the library which was passed along
Xwith the .LIBMEMBER attribute (see the MAKING LIBRARIES section).
XThe bound file name assigned to a target which is successfully
Xlocated in a library is the same name that would be assigned had the search
Xfailed (see 5.).
X.IP 5.
XThe search failed. Either the target was not found in any of the search
Xdirectories or no applicable .SOURCE special targets exist.
XIf applicable .SOURCE special targets exist, but the target was not found,
Xthen \fBdmake\fP assigns the first name searched as the bound file name.
XIf no applicable .SOURCE special targets exist,
Xthen the full original target name becomes the bound file name.
X.RE
X.PP
XThere is potential here for a lot of search operations. The trick is to
Xdefine .SOURCE.x special targets with short search lists and leave .SOURCE
Xas short as possible.
XThe search algorithm has the following useful side effect.
XWhen a target having the .LIBMEMBER (library member) attribute is searched for,
Xit is first searched for as an ordinary file.
XWhen a number of library members require updating it is desirable to compile
Xall of them first and to update the library at the end in a single operation.
XIf one of the members does not compile and \fBdmake\fP stops, then
Xthe user may fix the error and make again. \fBdmake\fP will not remake any
Xof the targets whose object files have already been generated as long as
Xnone of their prerequisite files have been modified as a result of the fix.
X.PP
XWhen defining .SOURCE and .SOURCE.x targets the construct
X.sp
X\t.SOURCE :
X.br
X\t.SOURCE : fred gery
X.sp
Xis equivalent to
X.sp
X\t.SOURCE :- fred gery
X.PP
X\fBdmake\fP correctly handles the UNIX Make variable VPATH. By definition VPATH
Xcontains a list of ':' separated directories to search when looking for a
Xtarget. \fBdmake\fP maps VPATH to the following special rule:
X.sp
X\t.SOURCE :^ $(VPATH:s/:/ /)
X.sp
XWhich takes the value of VPATH and sets .SOURCE to the same set of directories
Xas specified in VPATH.
X.SH "PERCENT(%) RULES AND MAKING INFERENCES"
XWhen \fBdmake\fP makes a target it's set of prerequisites (if any)
Xmust exist and the target must have a recipe which \fBdmake\fP
Xcan use to make it.
XIf the makefile does not specify an explicit recipe for the target then
X.B dmake
Xuses special rules to try to infer a recipe which it can use
Xto make the target. Previous versions of Make perform this task by using
Xrules that are defined by targets of the form .<suffix>.<suffix> and by
Xusing the .SUFFIXES list of suffixes. The exact workings of this mechanism
Xwere sometimes difficult to understand and often limiting in their usefulness.
XInstead, \fBdmake\fP supports the concept of \fI%-meta\fP rules.
XThe syntax and semantics of these rules differ from standard rule lines as
Xfollows:
X.sp
X.nf
X.RS
X\fI<%-target>\fP [\fI<attributes>\fP] \fI<ruleop>\fP [\fI<%-prerequisites>\fP] [;\fI<recipe>\fP]
X.RE
X.fi
X.sp
Xwhere \fI%-target\fP is a target containing exactly a single `%' sign,
X.I attributes
Xis a list (possibly empty) of attributes,
X.I ruleop
Xis the standard set of rule operators,
X.I "%-prerequisites"
X\&, if present, is a list of prerequisites containing zero or more `%' signs,
Xand
X.I recipe,
Xif present, is the first line of the recipe.
X.PP
XThe
X.I %-target
Xdefines a pattern against which a target whose recipe is
Xbeing inferred gets matched. The pattern match goes as follows: all chars are
Xmatched exactly from left to right up to but not including the % sign in the
Xpattern, % then matches the longest string from the actual target name
Xnot ending in
Xthe suffix given after the % sign in the pattern.
XConsider the following examples:
X.RS
X.sp
X.nf
X.Is "dir/%.c "
X.Ii "%.c"
Xmatches fred.c but not joe.c.Z
X.Ii "dir/%.c"
Xmatches dir/fred.c but not dd/fred.c
X.Ii "fred/%"
Xmatches fred/joe.c but not f/joe.c
X.Ii "%"
Xmatches anything
X.fi
X.sp
X.RE
XIn each case the part of the target name that matched the % sign is retained
Xand is substituted for any % signs in the prerequisite list of the %-meta rule
Xwhen the rule is selected during inference and
X.B dmake
Xconstructs the dependency specified by the %-meta rule for the actual target.
XAs an example the following %-meta rules describe the following:
X.RS
X.sp
X%.c : %.y ; recipe...
X.sp
X.RE
Xdescribes how to make any file ending in .c if a corresponding file ending
Xin .y can be found.
X.RS
X.sp
Xfoo%.o : fee%.k ; recipe...
X.sp
X.RE
Xis used to describe how to make fooxxxx.o from feexxxx.k.
X.RS
X.sp
X%.a :; recipe...
X.sp
X.RE
Xdescribes how to make a file whose suffix is .a without inferring any
Xprerequisites.
X.RS
X.sp
X%.c : %.y yaccsrc/%.y ; recipe...
X.sp
X.RE
Xis a short form for the construct:
X.RS
X.sp
X%.c : %.y ; recipe...
X.br
X%.c : yaccsrc/%.y ; recipe...
X.sp
X.RE
Xie. It is possible to specify the same recipe for two %-rules by giving
Xmore than one prerequisite in the prerequisite list.
XA more interesting example is:
X.RS
X.sp
X% : RCS/%,v ; co $@
X.sp
X.RE
Xwhich describes how to take any target and check it out of
Xthe RCS directory if the corresponding file exists in the RCS directory.
XThe equivalent SCCS rule would be:
X.RS
X.sp
X% : s.% ; get $@
X.sp
X.RE
X.PP
XThe previous RCS example defines an infinite rule, because it says how to make
X.I anything
Xfrom RCS/%,v, and
X.I anything
Xalso includes RCS/fred.c,v.
XTo limit the size of the graph that results from such rules
X.B dmake
Xuses the macro variable PREP (stands for % repetition). By default the value
Xof this variable is 0, which says that no repetitions of a %-rule are to be
Xgenerated. If it is set to something greater than 0, then that many
Xrepetitions of any infinite %-rule are allowed. If in the above
Xexample PREP was set to 1, then \fBdmake\fP would generate the dependency
Xgraph:
X.RS
X.sp
X% --> RCS/%,v --> RCS/RCS/%,v,v
X.sp
X.RE
XWhere each link is assigned the same recipe as the first link.
XPREP should be used only in special cases, since it may result in
Xa large increase in the number of possible prerequisites tested.
X.PP
X.B dmake
Xsupports dynamic prerequisite generation for prerequisites of %-meta rules.
XThis is best illustrated by an example. The RCS rule shown above can infer
Xhow to check out a file from a corresponding RCS file only if the target
Xis a simple file name with no directory information. That is, the above rule
Xcan infer how to find \fIRCS/fred.c,v\fP from the target \fIfred.c\fP,
Xbut cannot infer how to find \fIsrcdir/RCS/fred.c,v\fP from \fIsrcdir/fred.c\fP
Xbecause the above rule will cause \fBdmake\fP to look for RCS/srcdir/fred.c,v;
Xwhich does not exist (assume that srcdir has it's own RCS directory as is the
Xcommon case).
X.PP
XA more versatile formulation of the above RCS check out rule is the following:
X.RS
X.sp
X% : $$(@:d)RCS/$$(@:f),v : co $@
X.sp
X.RE
XThis rule uses the dynamic macro $@ to specify the prerequisite to try to
Xinfer. During inference of this rule the macro $@ is set to the value of
Xthe target of the %-meta rule and the appropriate prerequisite is generated by
Xextracting the directory portion of the target name (if any), appending the
Xstring \fIRCS/\fP to it, and appending the target file name with a trailing
X\fI,v\fP attached to the previous result.
X.PP
X.B dmake
Xcan also infer indirect prerequisites.
XAn inferred target can have a list of prerequisites added that will not
Xshow up in the value of $< but will show up in the value of $? and $&.
XIndirect prerequisites are specified in an inference rule by quoting the
Xprerequisite with single quotes. For example, if you had the explicit
Xdependency:
X.RS
X.sp
X.nf
Xfred.o : fred.c ; rule to make fred.o
Xfred.o : local.h
X.fi
X.sp
X.RE
Xthen this can be infered for fred.o from the following inference rule:
X.RS
X.sp
X%.o : %.c 'local.h' ; rule to make a .o from a .c
X.sp
X.RE
XYou may infer indirect prerequisites that are a function of the value of '%'
Xin the current rule. The meta-rule:
X.RS
X.sp
X%.o : %.c '$(INC)/%.h' ; rule to make a .o from a .c
X.sp
X.RE
Xinfers an indirect prerequisite found in the INC directory whose name is the
Xsame as the expansion of $(INC), and the prerequisite name depends on the
Xbase name of the current target.
XThe set of indirect prerequisites is attached to the meta rule in which they
Xare specified and are inferred only if the rule is used to infer a recipe
Xfor a target. They do not play an active role in driving the inference
Xalgorithm.
XThe construct:
X.RS
X.sp
X%.o : %.c %.f 'local.h'; recipe
X.sp
X.RE
Xis equivalent to:
X.RS
X.sp
X.nf
X%.o : %.c 'local.h' : recipe
X%.o : %.f 'local.h' : recipe
X.fi
X.sp
X.RE
X.PP
XIf any of the attributes .SETDIR, .EPILOG, .PROLOG, .SILENT,
X\&.USESHELL, .SWAP, .PRECIOUS, .LIBRARY, and .IGNORE
Xare given for a %-rule then when that rule is bound to a target
Xas the result of an inference, the target's set of attributes is augmented by
Xthe attributes from the above set that are specified in the bound %-rule.
XOther attributes specified for %-meta rules are not inherited by the target.
XThe .SETDIR attribute is treated in a special way.
XIf the target already had a .SETDIR attribute set and the bound %-rule also
Xspecified a .SETDIR attribute then the one
Xoriginally specified with the target prevails.
XDuring inference any .SETDIR attributes for the inferred prerequisite
Xare honored.
XThe directories must exist for a %-meta rule to be selected as a possible
Xinference path. If the directories do not exist no error message is issued,
Xinstead the corresponding path in the inference graph is simply rejected.
X.PP
X.B dmake
Xalso supports the old format special target .<suffix>.<suffix>
Xby identifying any rules
Xof this form and mapping them to the appropriate %-rule. So for example if
Xan old makefile contains the construct:
X.RS
X.sp
X\&.c.o :; cc -c $< -o $@
X.sp
X.RE
X.B dmake
Xmaps this into the following %-rule:
X.RS
X.sp
X%.o : %.c; cc -c $< -o $@
X.sp
X.RE
XFurthermore,
X.B dmake
Xunderstands several SYSV AUGMAKE special targets and maps them into
Xcorresponding %-meta rules. These transformation must be enabled by providing
Xthe -A flag on the command line or by setting the value of AUGMAKE to non
XNULL.
XThe construct
X.RS
X.sp
X\&.suff :; recipe
X.sp
X.RE
Xgets mapped into:
X.RS
X.sp
X% : %.suff; recipe
X.sp
X.RE
Xand the construct
X.RS
X.sp
X\&.c~.o :; recipe
X.sp
X.RE
Xgets mapped into:
X.RS
X.sp
X%.o : s.%.c ; recipe
X.sp
X.RE
XIn general, a special target of the form .<str>~ is replaced by the %-rule
Xconstruct s.%.<str>, thereby providing support for the syntax used by SYSV
XAUGMAKE for providing SCCS support.
XWhen enabled, these mappings allow processing of existing SYSV
Xmakefiles without modifications.
X.PP
X.B dmake
Xbases all of it's inferences on the inference graph constructed from the
X%-rules defined in the makefile.
XIt knows exactly which targets can be made from which prerequisites by
Xmaking queries on the inference graph. For this reason .SUFFIXES is not
Xneeded and is completely ignored.
X.PP
XFor a %-meta rule to be inferred as the
Xrule whose recipe will be used to make a target, the target's name must match
Xthe %-target pattern, and any inferred %-prerequisite must already exist or
Xhave an explicit recipe so that the prerequisite can be made.
XWithout \fItransitive closure\fP on the inference graph the above rule
Xdescribes precisely when an inference match terminates the search.
XIf transitive closure is enabled (the usual case), and a prerequisite does
Xnot exist or cannot be made, then
X.B dmake
Xinvokes the inference algorithm recursively on the prerequisite to see if
Xthere is some way the prerequisite can be manufactured. For if the
Xprerequisite can be made then the current target can also be made using the
Xcurrent %-meta rule.
XThis means that there is no longer a need to give a rule
Xfor making a .o from a .y if you have already given a rule for making a .o
Xfrom a .c and a .c from a .y. In such cases
X.B dmake
Xcan infer how to make the
X\&.o from the .y via the intermediary .c and will remove the .c when the .o is
Xmade. Transitive closure can be disabled by giving the -T switch on the
Xcommand line.
X.PP
XA word of caution.
X.B dmake
Xbases its transitive closure on the %-meta rule targets.
XWhen it performs transitive closure it infers how to make a target from a
Xprerequisite by performing a pattern match as if the potential prerequisite
Xwere a new target.
XThe set of rules:
X.RS
X.nf
X.sp
X%.o : %.c :; rule for making .o from .c
X%.c : %.y :; rule for making .c from .y
X% : RCS/%,v :; check out of RCS file
X.fi
X.sp
X.RE
Xwill, by performing transitive closure, allow \fBdmake\fP to infer how to make
Xa .o from a .y using a .c as an intermediate temporary file. Additionally
Xit will be able to infer how to make a .y from an RCS file, as long as that
XRCS file is in the RCS directory and has a name which ends in .y,v.
XThe transitivity computation is performed dynamically for each target that
Xdoes not have a recipe. This has potential to be very slow if the %-meta
Xrules are not carefully specified. The .NOINFER attribute is used to mark
Xa %-meta node as being a final target during inference. Any node with this
Xattribute set will not be used for subsequent inferences. As an example
Xthe node RCS/%,v is marked as a final node since we know that if the RCS file
Xdoes not exist there likely is no other way to make it. Thus the standard
Xstartup makefile contains the entry:
X.RS
X.nf
X\&.NOINFER : RCS/%,v
X.fi
X.RE
XThereby indicating that the RCS file is the end of the inference chain.
X.PP
X.B dmake
Xtries to
Xremove intermediate files resulting from transitive closure if the file
Xis not marked as being PRECIOUS, or the \fB-u\fP flag was not given on the
Xcommand line, and if the inferred intermediate did not previously exist.
XIntermediate targets that existed prior to being made are never removed.
XThis is in keeping with the philosophy that
X.B dmake
Xshould never remove things from the file system that it did not add.
XIf the special target .REMOVE is defined and has a recipe then
X.B dmake
Xconstructs a list of the intermediate files to be removed and makes them
Xprerequisites of .REMOVE. It then makes .REMOVE thereby removing the
Xprerequisites if the recipe of .REMOVE says to. Typically .REMOVE is defined
Xin the startup file as:
X.sp
X\t".REMOVE :; $(RM) $<".
X.SH "MAKING TARGETS"
XIn order to update a target \fBdmake\fP must execute a recipe.
XWhen a recipe needs to be executed it is first expanded so that any macros
Xin the recipe text are expanded, and it is then either executed directly or
Xpassed to a shell.
X.B dmake
Xsupports two types of recipes. The regular recipes and group recipes.
X.PP
XWhen a regular recipe is invoked \fBdmake\fP executes each line of the recipe
Xseparately using a new copy of a shell if a shell is required.
XThus effects of commands do not generally persist across recipe lines.
X(e.g. cd requests in a recipe line do not carry over to the next recipe line)
XThe decision on whether a shell is required to execute a command is based on
Xthe value of the macro SHELLMETAS or on the specification of '+' or .USESHELL
Xfor the current recipe or target respectively.
XIf any character in the value of
XSHELLMETAS is found in the expanded recipe text-line or the use of a shell
Xis requested explicitly via '+' or .USESHELL then the command is
Xexecuted using a shell, otherwise the command is executed directly.
XThe shell that is used for execution is given by the value of the macro SHELL.
XThe flags that are passed to the shell are given by the value of SHELLFLAGS.
XThus \fBdmake\fP constructs the command line:
X.sp
X\t$(SHELL) $(SHELLFLAGS) $(expanded_recipe_command)
X.sp
XNormally
X.B dmake
Xwrites the command line that it is about to invoke to standard output.
XIf the .SILENT attribute is set for the target or for
Xthe recipe line (via @), then the recipe line is not echoed.
X.PP
XGroup recipe processing is similar to that of regular recipes, except that
Xa shell is always invoked. The shell that is invoked is given by the value of
Xthe macro GROUPSHELL, and its flags are taken from the value of the macro
XGROUPFLAGS. If a target has the .PROLOG attribute set then
X.B dmake
Xprepends to the shell script the recipe associated with the special target
X\&.GROUPPROLOG, and if the attribute .EPILOG is set as well, then the recipe
Xassociated with the special target .GROUPEPILOG is appended to the script
Xfile.
XThis facility can be used to always prepend a common header and common trailer
Xto group recipes.
XGroup recipes are echoed to standard output just like standard recipes, but
Xare enclosed by lines beginning with [ and ].
X.SH "MAKING LIBRARIES"
XLibraries are easy to maintain using \fBdmake\fP. A library is a file
Xcontaining a collection of object files.
XThus to make a library you simply specify it as a target with the .LIBRARY
Xattribute set and specify its list of prerequisites. The prerequisites should
Xbe the object members that are to go into the library. When
X.B dmake
Xmakes the library target it uses the .LIBRARY attribute to pass to the
Xprerequisites the .LIBMEMBER attribute and the name of the library. This
Xenables the file binding mechanism to look for the member in the library if an
Xappropriate object file cannot be found. A small example best illustrates
Xthis.
X.RS
X.nf
X.sp
Xmylib.a .LIBRARY : mem1.o mem2.o mem3.o
X\trules for making library...
X\t# remember to remove .o's when lib is made
X.sp
X# equivalent to: '%.o : %.c ; ...'
X\&.c.o :; rules for making .o from .c say
X.sp
X.fi
X.RE
X.B dmake
Xwill use the .c.o rule for making the library members if appropriate .c files
Xcan be found using the search rules. NOTE: this is not specific in any way
Xto C programs, they are simply used as an example.
X.PP
X.B dmake
Xtries to handle the old library construct format in a sensible way.
XThe construct
X.I lib(member.o)
Xis separated and the \fIlib\fP portion is declared
Xas a library target.
XThe new target is defined
Xwith the .LIBRARY attribute set and the \fImember.o\fP portion of the
Xconstruct is
Xdeclared as a prerequisite of the lib target.
XIf the construct \fIlib(member.o)\fP
Xappears as a prerequisite of a target in the
Xmakefile, that target has the new name of the lib assigned as it's
Xprerequisite. Thus the following example:
X.RS
X.sp
X.nf
Xa.out : ml.a(a.o) ml.a(b.o); $(CC) -o $@ $<
X
X\&.c.o :; $(CC) -c $(CFLAGS) -o $@ $<
X%.a:
X\tar rv $@ $<
X\tranlib $@
X\trm -rf $<
X.sp
X.fi
X.RE
Xconstructs the following dependency
Xgraph.
X.RS
X.sp
X.nf
Xa.out : ml.a; $(CC) -o $@ $<
Xml.a .LIBRARY : a.o b.o
X
X%.o : %.c ; $(CC) -c $(CFLAGS) -o $@ $<
X%.a :
X\tar rv $@ $<
X\tranlib $@
X\trm -rf $<
X.sp
X.fi
X.RE
Xand making a.out then works as expected.
X.PP
XThe same thing happens for any target of the form \fIlib((entry))\fP.
XThese targets have an
Xadditional feature in that the \fIentry\fP target has the .SYMBOL attribute
Xset automatically.
X.PP
XNOTE: If the notion of entry points is supported by the archive and by
X\fBdmake\fP (currently not the case) then
X.B dmake
Xwill search the archive for the entry point and return not only the
Xmodification time of the member which defines the entry but also the name of
Xthe member file. This name will then replace \fIentry\fP and will be used for
Xmaking the member file. Once bound to an archive member the .SYMBOL
Xattribute is removed from the target.
XThis feature is presently disabled as there is little standardization
Xamong archive formats, and we have yet to find a makefile utilizing this
Xfeature (possibly due to the fact that it is unimplemented in most versions
Xof UNIX Make).
X.SH "MULTI PROCESSING"
XIf the architecture supports it then \fBdmake\fP is capable of making a target's
Xprerequisites in parallel. \fBdmake\fP will make as much in parallel as it
Xcan and use a number of child processes up to the maximum specified by
XMAXPROCESS or by the value supplied to the -P command line flag.
XA parallel make is enabled by setting the value of MAXPROCESS (either directly
Xor via -P option) to a value which is > 1.
X\fBdmake\fP guarantees that all dependencies as specified in the makefile are
Xhonored. A target will not be made until all of its prerequisites have been
Xmade.
XIf a parallel make is being performed then the following restrictions on
Xparallelism are enforced.
X.RS
X.IP 1.
XIndividual recipe lines in a non-group recipe are performed sequentially in
Xthe order in which they are specified within the makefile and in parallel with
Xthe recipes of other targets.
X.IP 2.
XIf a target contains multiple recipe definitions (cf. :: rules) then these are
Xperformed sequentially in the order in which the :: rules are specified within
Xthe makefile and in parallel with the recipes of other targets.
X.IP 3.
XIf a target rule contains the `!' modifier, then the recipe is performed
Xsequentially for the list of outdated prerequisites and in parallel with the
Xrecipes of other targets.
X.IP 4.
XIf a target has the .SEQUENTIAL attribute set then all of its prerequisites
Xare made sequentially relative to one another (as if MAXPROCESS=1), but in
Xparallel with other targets in the makefile.
X.RE
X.PP
XNote: If you specify a parallel make then
Xthe order of target update and the order in which the associated recipes are
Xinvoked will not correspond to that displayed by the -n flag.
X.SH "CONDITIONALS"
X.B dmake
Xsupports a makefile construct called a \fIconditional\fR. It allows
Xthe user
Xto conditionally select portions of makefile text for input processing
Xand to discard other portions. This becomes useful for
Xwriting makefiles that are intended to function for more than one target
Xhost and environment. The conditional expression is specified as follows:
X.sp
X.RS
X.nf
X\&.IF \fIexpression\fR
X ... if text ...
X\&.ELSE
X ... else text ...
X\&.END
X.RE
X.fi
X.sp
XThe .ELSE portion is optional, and the conditionals may be nested (ie.
Xthe text may contain another conditional).
X\&.IF, .ELSE, and .END
Xmay appear anywhere in the makefile, but a single conditional expression
Xmay not span multiple makefiles.
X.PP
X\fIexpression\fR can be one of the following three forms:
X.sp
X\t<text> | <text> == <text> | <text> != <text>
X.sp
Xwhere \fItext\fR is either text or a macro expression. In any case,
Xbefore the comparison is made, the expression is expanded. The text
Xportions are then selected and compared. White space at the start and
Xend of the text portion is discarded before the comparison. This means
Xthat a macro that evaluates to nothing but white space is considered a
XNULL value for the purpose of the comparison.
XIn the first case the expression evaluates TRUE if the text is not NULL
Xotherwise it evaluates FALSE. The remaining two cases both evaluate the
Xexpression on the basis of a string comparison.
XIf a macro expression needs to be equated to a NULL string then compare it to
Xthe value of the macro $(NULL).
X.SH "EXAMPLES"
X.RS
X.nf
X.sp
X# A simple example showing how to use make
X#
Xprgm : a.o b.o
X cc a.o b.o -o prgm
Xa.o : a.c g.h
X cc a.c -o $@
Xb.o : b.c g.h
X cc b.c -o $@
X.fi
X.RE
X.sp
XIn the previous
Xexample prgm is remade only if a.o and/or b.o is out of date with
Xrespect to prgm.
XThese dependencies can be stated more concisely
Xby using the inference rules defined in the standard startup file.
XThe default rule for making .o's from .c's looks something like this:
X.sp
X\&\t%.o : %.c; cc -c $(CFLAGS) -o $@ $<
X.sp
XSince there exists a rule (defined in the startup file)
Xfor making .o's from .c's
X\fBdmake\fR will use that rule
Xfor manufacturing a .o from a .c and we can specify our dependencies
Xmore concisely.
X.sp
X.RS
X.nf
Xprgm : a.o b.o
X cc -o prgm $<
Xa.o b.o : g.h
X.fi
X.RE
X.sp
XA more general way to say the above using the new macro expansions
Xwould be:
X.sp
X.RS
X.nf
XSRC = a b
XOBJ = {$(SRC)}.o
X.sp
Xprgm : $(OBJ)
X cc -o $@ $<
X.sp
X$(OBJ) : g.h
X.fi
X.RE
X.sp
XIf we want to keep the objects in a separate directory, called
Xobjdir, then we would write
Xsomething like this.
X.sp
X.RS
X.nf
XSRC = a b
XOBJ = {$(SRC)}.o
X.sp
Xprgm : $(OBJ)
X cc $< -o $@
X.sp
X$(OBJ) : g.h
X\&%.o : %.c
X $(CC) -c $(CFLAGS) -o $(@:f) $<
X mv $(@:f) objdir
X
X\&.SOURCE.o : objdir # tell make to look here for .o's
X.fi
X.RE
X.sp
XAn example of building library members would go something like this:
X(NOTE: The same rules as above will be used to produce .o's from .c's)
X.sp
X.RS
X.nf
XSRC\t= a b
XLIB\t= lib
XLIBm\t= { $(SRC) }.o
X.sp
Xprgm: $(LIB)
X cc -o $@ $(LIB)
X.sp
X$(LIB) .LIBRARY : $(LIBm)
X ar rv $@ $<
X rm $<
X.fi
X.RE
X.sp
XFinally, suppose that each of the source files in the previous example had
Xthe `:' character in their target name. Then we would write the above example
Xas:
X.sp
X.RS
X.nf
XSRC\t= f:a f:b
XLIB\t= lib
XLIBm\t= "{ $(SRC) }.o" # put quotes around each token
X.sp
Xprgm: $(LIB)
X cc -o $@ $(LIB)
X.sp
X$(LIB) .LIBRARY : $(LIBm)
X ar rv $@ $<
X rm $<
X.fi
X.RE
X.SH "COMPATIBILITY"
XThere are two notable differences between
X.B \fBdmake\fR
Xand the standard version of BSD UNIX 4.2/4.3 Make.
X.RS
X.IP 1. .3i
XBSD UNIX 4.2/4.3 Make supports wild card filename expansion for
Xprerequisite names. Thus if a directory contains a.h, b.h and c.h, then a
Xline like
X.sp
X\ttarget: *.h
X.sp
Xwill cause UNIX make to expand the *.h into "a.h b.h c.h". \fBdmake\fR
Xdoes not support this type of filename expansion.
X.IP 2. .3i
XUnlike UNIX make, touching a library member causes \fBdmake\fR
Xto search the library for the member name and to update the library time stamp.
XThis is only implemented in the UNIX version.
XMSDOS and other versions may not have librarians that keep file time stamps,
Xas a result \fBdmake\fR touches the library file itself, and prints a warning.
X.RE
X.PP
X\fBdmake\fP is not compatible with GNU Make. In particular it does not
Xunderstand GNU Make's macro expansions that query the file system.
X.PP
X.B dmake
Xis fully compatible with SYSV AUGMAKE, and supports the following AUGMAKE
Xfeatures:
X.RS
X.IP 1. .3i
XThe word \fBinclude\fP appearing at the start of a line can be used instead of
Xthe ".INCLUDE :" construct understood by \fBdmake\fP.
X.IP 2. .3i
XThe macro modifier expression $(macro:str=sub) is understood and is equivalent
Xto the expression $(macro:s/str/sub), with the restriction that str must match
Xthe following regular expression:
X.sp
X\tstr[ |\\t][ |\\t]*
X.sp
X(ie. str only matches at the end of a token where str is a suffix and is
Xterminated by a space, a tab, or end of line)
X.IP 3.
XThe macro % is defined to be $@ (ie. $% expands to the same value as $@).
X.IP 4.
XThe AUGMAKE notion of libraries is handled correctly.
X.IP 5.
XWhen defining special targets for the inference rules and the AUGMAKE special
Xtarget mapping is enabled then the special target
X\&.X is equivalent to the %-rule "% : %.X".
X.RE
X.SH "LIMITS"
XIn some environments the length of an argument string is restricted.
X(e.g. MSDOS command line arguments cannot be longer than 128 bytes if you are
Xusing the standard command.com command interpreter as your shell,
X.B dmake
Xtext diversions may help in these situations.)
X.SH "PORTABILITY"
XTo write makefiles that can be moved from one environment to another requires
Xsome forethought. In particular you must define as macros all those things
Xthat may be different in the new environment.
X.B dmake
Xhas two facilities that help to support writing portable makefiles, recursive
Xmacros and conditional expressions. The recursive macros, allow one to define
Xenvironment configurations that allow different environments for similar types
Xof operating systems. For example the same make script can be used for SYSV and
XBSD but with different macro definitions.
X.PP
XTo write a makefile that is portable between UNIX and MSDOS requires both
Xfeatures since in almost all cases you will need to define new recipes for
Xmaking targets. The recipes will probably be quite different since the
Xcapabilities of the tools on each machine are different. Different
Xmacros will be needed to help handle the smaller differences in the two
Xenvironments.
X.PP
XNOTE: Unlike UNIX, MSDOS \fBdoes\fP maintain cd requests
Xcross single recipe lines.
XThis is not portable, and your makefiles will not work the same way if you
Xdepend on it. Use the .IF ... .ELSE ... .END conditionals to supply different
Xmake scripts as necessary.
X.SH FILES
XMakefile, makefile, startup.mk (use dmake -V to tell you where the startup
Xfile is)
X.SH "SEE ALSO"
Xsh(1), csh(1), touch(1), f77(1), pc(1), cc(1)
X.br
XS.I. Feldman \fIMake - A Program for Maintaining Computer Programs\fP
X.SH "AUTHOR"
XDennis Vadura, CS Dept. University of Waterloo. dvadura@watdragon.uwaterloo.ca
X.br
XMany thanks to Carl Seger for his helpful suggestions,
Xand to Trevor John Thompson for his many excellent ideas and
Xinformative bug reports.
X.SH BUGS
XSome system commands return non-zero status inappropriately.
XUse
X.B \-i
X(`\-' within the makefile) to overcome the difficulty.
X.PP
XSome systems do not have easily accessible
Xtime stamps for library members (MSDOS, AMIGA, etc)
Xfor these \fBdmake\fR uses the time stamp of the library instead and prints
Xa warning the first time it does so. This is almost always ok, except when
Xmultiple makefiles update a single library file. In these instances it is
Xpossible to miss an update if one is not careful.
SHAR_EOF
echo "File man/dmake.tf is complete"
chmod 0440 man/dmake.tf || echo "restore of man/dmake.tf fails"
echo "x - extracting man/dmake.p (Text)"
sed 's/^X//' << 'SHAR_EOF' > man/dmake.p &&
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
XNNAAMMEE
X ddmmaakkee - maintain program groups, or interdependent files
X
XSSYYNNOOPPSSIISS
X ddmmaakkee [-AeEhiknpqersStTuvVx] [-P#] [macro[*][+][:]=_v_a_l_u_e]
X [-f file] [target ...]
X
XDDEESSCCRRIIPPTTIIOONN
X ddmmaakkee executes commands found in an external file called a
X _m_a_k_e_f_i_l_e to update one or more target names. Each target
X may depend on zero or more prerequisite targets. If any of
X the target's prerequisites is newer than the target or if
X the target itself does not exist, then ddmmaakkee will attempt to
X make the target.
X
X If no --ff command line option is present then ddmmaakkee searches
X for an existing _m_a_k_e_f_i_l_e from the list of prerequisites
X specified for the special target _._M_A_K_E_F_I_L_E_S (see the STARTUP
X section for more details). If "-" is the name of the file
X specified to the --ff flag then ddmmaakkee uses standard input as
X the source of the makefile text.
X
X Any macro definitions (arguments with embedded "=" signs)
X that appear on the command line are processed first and
X supercede definitions for macros of the same name found
X within the makefile. In general it is impossible for defin-
X itions found inside the makefile to redefine a macro defined
X on the command line, see the MACROS section for an excep-
X tion.
X
X If no _t_a_r_g_e_t names are specified on the command line, then
X ddmmaakkee uses the first non-special target found in the
X makefile as the default target. See the SSPPEECCIIAALL TTAARRGGEETTSS
X section for the list of special targets and their function.
X ddmmaakkee is a re-implementation of the UNIX Make utility with
X significant enhancements. Makefiles written for most previ-
X ous versions of _m_a_k_e will be handled correctly by ddmmaakkee..
X Known differences between ddmmaakkee and other versions of make
X are discussed in the CCOOMMPPAATTIIBBIILLIITTYY section found at the end
X of this document.
X
XOOPPTTIIOONNSS
X --AA Enable AUGMAKE special inference rule transformations
X (see the "PERCENT(%) RULES" section), these are set to
X off by default.
SHAR_EOF
echo "End of part 12"
echo "File man/dmake.p is continued in part 13"
echo "13" > s2_seq_.tmp
exit 0