dvadura@watdragon.waterloo.edu (Dennis Vadura) (05/12/91)
Submitted-by: Dennis Vadura <dvadura@watdragon.waterloo.edu>
Posting-number: Volume 19, Issue 35
Archive-name: dmake/part14
Supersedes: dmake-3.6: Volume 15, Issue 52-77
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#!/bin/sh
# this is dmake.shar.14 (part 14 of a multipart archive)
# do not concatenate these parts, unpack them in order with /bin/sh
# file dmake/man/dmake.nc continued
#
if test ! -r _shar_seq_.tmp; then
echo 'Please unpack part 1 first!'
exit 1
fi
(read Scheck
if test "$Scheck" != 14; then
echo Please unpack part "$Scheck" next!
exit 1
else
exit 0
fi
) < _shar_seq_.tmp || exit 1
if test -f _shar_wnt_.tmp; then
sed 's/^X//' << 'SHAR_EOF' >> 'dmake/man/dmake.nc' &&
X files to be handed to the command inter-
X preter. For example, if it is defined as
X .sh, then all temporary files created by
X dmake will end in the suffix .sh. Under
X MSDOS if you are using command.com as your
X GROUPSHELL, then this suffix must be set to
X .bat in order for group recipes to function
X correctly. The setting of GROUPSUFFIX and
X GROUPSHELL is done automatically for
X command.com in the startup.mk files.
X
X MAKE Is defined in the startup file by default.
X The string $(MAKE) is recognized when using
X the -n option for single line recipes. Ini-
X tially this macro is defined to have the
X value "$(MAKECMD) $(MFLAGS)".
X
X MAKESTARTUP This macro defines the full path to the ini-
X tial startup makefile. Use the -V command
X line option to discover its initial value.
X
X
X
X
X
Version 3.70 UW 27
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X MAXLINELENGTH This macro defines the maximum size of a
X single line of makefile input text. The
X size is specified as a number, the default
X value is defined internally and is shown via
X the -V option. A buffer of this size plus 2
X is allocated for reading makefile text. The
X buffer is freed before any targets are made,
X thereby allowing files containing long input
X lines to be processed without consuming
X memory during the actual make.
X
X MAXPROCESS Specify the maximum number of child
X processes to use when making targets. The
X default value of this macro is "1" and its
X value cannot exceed the value of the macro
X MAXPROCESSLIMIT. Setting the value of MAX-
X PROCESS on the command line or in the
X makefile is equivalent to supplying a
X corresponding value to the -P flag on the
X command line.
X
X PREP This macro defines the number of iterations
X to be expanded automatically when processing
X % rule definitions of the form:
X
X % : %.suff
X
X See the sections on PERCENT(%) RULES for
X details on how PREP is used.
X
X SHELL This macro defines the full path to the exe-
X cutable image to be used as the shell when
X processing single line recipes. This macro
X must be defined if recipes requiring the
X shell for execution are to be used. It is
X assigned a default value in the startup
X makefile. Under UNIX this value is /bin/sh.
X
X SHELLFLAGS This macro gives the set of flags to pass to
X the shell when invoking it to execute a sin-
X gle line recipe. The value of the macro is
X the list of flags with a leading switch
X indicator. (ie. `-' under UNIX)
X
X SHELLMETAS Each time dmake executes a single recipe
X line (not a group recipe) the line is
X searched for any occurrence of a character
X defined in the value of SHELLMETAS. If such
X a character is found the recipe line is
X defined to require a shell to ensure its
X correct execution. In such instances a
X shell is used to invoke the recipe line. If
X
X
X
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X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X no match is found the recipe line is exe-
X cuted without the use of a shell.
X
X
X There is only one character valued macro defined by dmake:
X SWITCHAR contains the switch character used to introduce
X options on command lines. For UNIX its value is '-', and
X for MSDOS its value may be '/' or '-'. The macro is inter-
X nally defined and is not user setable. The MSDOS version of
X dmake attempts to first extract SWITCHAR from an environment
X variable of the same name. If that fails it then attempts
X to use the undocumented getswitchar system call, and returns
X the result of that. Under MSDOS version 4.0 you must set
X the value of the environment macro SWITCHAR to '/' to obtain
X predictable behavior.
X
X All boolean macros currently understood by dmake correspond
X directly to the previously defined attributes. These macros
X provide a second way to apply global attributes, and
X represent the preferred method of doing so. They are used
X by assigning them a value. If the value is not a NULL
X string then the boolean condition is set to on. If the
X value is a NULL string then the condition is set to off.
X There are five conditions defined and they correspond
X directly to the attributes of the same name. Their meanings
X are defined in the ATTRIBUTES section above. The macros
X are: .EPILOG, .IGNORE, .MKSARGS, .NOINFER, .PRECIOUS, .PRO-
X LOG, .SEQUENTIAL, .SILENT, .SWAP, and .USESHELL. Assigning
X any of these a non NULL value will globally set the
X corresponding attribute to on.
X
RUN_TIME MACROS
X These macros are defined when dmake is making targets, and
X may take on different values for each target. $@ is defined
X to be the full target name, $? is the list of all out of
X date prerequisites, $& is the list of all prerequisites, $>
X is the name of the library if the current target is a
X library member, and $< is the list of prerequisites speci-
X fied in the current rule. If the current target had a
X recipe inferred then $< is the name of the inferred prere-
X quisite even if the target had a list of prerequisites sup-
X plied using an explicit rule that did not provide a recipe.
X In such situations $& gives the full list of prerequisites.
X
X $* is defined as $(@:db) when making targets with explicit
X recipes and is defined as the value of % when making targets
X whose recipe is the result of an inference. In the first
X case $* is the target name with no suffix, and in the second
X case, is the value of the matched % pattern from the associ-
X ated %-rule. $^ expands to the set of out of date prere-
X quisites taken from the current value of $<. In addition to
X these, $$ expands to $, {{ expands to {, }} expands to },
X
X
X
Version 3.70 UW 29
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X and the strings <+ and +> are recognized as respectively
X starting and terminating a text diversion when they appear
X literally together in the same input line.
X
X The difference between $? and $^ can best be illustrated by
X an example, consider:
X
X fred.out : joe amy hello
X rules for making fred
X
X fred.out : my.c your.h his.h her.h # more prerequisites
X
X Assume joe, amy, and my.c are newer then fred.out. When
X dmake executes the recipe for making fred.out the values of
X the following macros will be:
X
X $@ --> fred.out
X $* --> fred
X $? --> joe amy my.c # note the difference between $? and $^
X $^ --> joe amy
X $< --> joe amy hello
X $& --> joe amy hello my.c your.h his.h her.h
X
X
FUNCTION MACROS
X dmake supports a full set of functional macros. One of
X these, the $(mktmp ...) macro, is discussed in detail in the
X TEXT DIVERSION section and is not covered here.
X
X
X $(null,text true false)
X expands the value of text. If it is NULL then the
X macro returns the value of the expansion of true
X and the expansion of false otherwise. The terms
X true, and false must be strings containing no
X white-space.
X
X $(!null,text true false)
X Behaves identically to the previous macro except
X that the true string is chosen if the expansion of
X text is not NULL.
X
X $(eq,text_a,text_b true false)
X expands text_a and text_b and compares their
X results. If equal it returns the result of the
X expansion of the true term, otherwise it returns
X the expansion of the false term.
X
X $(!eq,text_a,text_b true false)
X Behaves identically to the previous macro except
X that the true string is chosen if the expansions
X of the two strings are not equal
X
X
X
Version 3.70 UW 30
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X $(shell command)
X Runs command as if it were part of a recipe and
X returns, separated by a single space, all the
X non-white space terms written to stdout by the
X command. For example:
X
X $(shell ls *.c)
X
X will return "a.c b.c c.c d.c" if the files exist
X in the current directory. The recipe modification
X flags [+@%-] are honored if they appear as the
X first characters in the command. For example:
X
X $(shell +ls *.c)
X
X will run the command using the current shell.
X
X $(sort list)
X Will take all white-space separated tokens in list
X and will return their sorted equivalent list.
X
X $(strip data)
X Will replace all strings of white-space in data by
X a single space.
X
X $(subst,pat,replacement data)
X Will search for pat in data and will replace any
X occurrence of pat with the replacement string.
X The expansion
X
X $(subst,.o,.c $(OBJECTS))
X
X is equivalent to:
X
X $(OBJECTS:s/.o/.c/)
X
X
DYNAMIC PREREQUISITES
X dmake looks for prerequisites whose names contain macro
X expansions during target processing. Any such prerequisites
X are expanded and the result of the expansion is used as the
X prerequisite name. As an example the line:
X
X fred : $$@.c
X
X causes the $$@ to be expanded when dmake is making fred, and
X it resolves to the target fred. This enables dynamic prere-
X quisites to be generated. The value of @ may be modified by
X any of the valid macro modifiers. So you can say for exam-
X ple:
X
X fred.out : $$(@:b).c
X
X
X
Version 3.70 UW 31
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X where the $$(@:b) expands to fred. Note the use of $$
X instead of $ to indicate the dynamic expansion, this is due
X to the fact that the rule line is expanded when it is ini-
X tially parsed, and $$ then returns $ which later triggers
X the dynamic prerequisite expansion. If you really want a $
X to be part of a prerequisite name you must use $$$$.
X Dynamic macro expansion is performed in all user defined
X rules, and the special targets .SOURCE*, and .INCLUDEDIRS.
X
BINDING TARGETS
X This operation takes a target name and binds it to an exist-
X ing file, if possible. dmake makes a distinction between
X the internal target name of a target and its associated
X external file name. Thus it is possible for a target's
X internal name and its external file name to differ. To per-
X form the binding, the following set of rules is used.
X Assume that we are trying to bind a target whose name is of
X the form X.suff, where .suff is the suffix and X is the stem
X portion (ie. that part which contains the directory and the
X basename). dmake takes this target name and performs a
X series of search operations that try to find a suitably
X named file in the external file system. The search opera-
X tion is user controlled via the settings of the various
X .SOURCE targets.
X
X 1. If target has the .SYMBOL attribute set then look
X for it in the library. If found, replace the tar-
X get name with the library member name and continue
X with step 2. If the name is not found then
X return.
X
X 2. Extract the suffix portion (that following the
X `.') of the target name. If the suffix is not
X null, look up the special target .SOURCE.<suff>
X (<suff> is the suffix). If the special target
X exists then search each directory given in the
X .SOURCE.<suff> prerequisite list for the target.
X If the target's suffix was null (ie. .suff was
X empty) then perform the above search but use the
X special target .SOURCE.NULL instead. If at any
X point a match is found then terminate the search.
X If a directory in the prerequisite list is the
X special name `.NULL ' perform a search for the
X full target name without prepending any directory
X portion (ie. prepend the NULL directory). (a
X default target of '.SOURCE : .NULL' is defined by
X dmake at startup, and is user redefinable)
X
X 3. The search in step 2. failed. Repeat the same
X search but this time use the special target
X .SOURCE.
X
X
X
X
Version 3.70 UW 32
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X 4. The search in step 3. failed. If the target has
X the library member attribute (.LIBMEMBER) set then
X try to find the target in the library which was
X passed along with the .LIBMEMBER attribute (see
X the MAKING LIBRARIES section). The bound file
X name assigned to a target which is successfully
X located in a library is the same name that would
X be assigned had the search failed (see 5.).
X
X 5. The search failed. Either the target was not
X found in any of the search directories or no
X applicable .SOURCE special targets exist. If
X applicable .SOURCE special targets exist, but the
X target was not found, then dmake assigns the first
X name searched as the bound file name. If no
X applicable .SOURCE special targets exist, then the
X full original target name becomes the bound file
X name.
X
X There is potential here for a lot of search operations. The
X trick is to define .SOURCE.x special targets with short
X search lists and leave .SOURCE as short as possible. The
X search algorithm has the following useful side effect. When
X a target having the .LIBMEMBER (library member) attribute is
X searched for, it is first searched for as an ordinary file.
X When a number of library members require updating it is
X desirable to compile all of them first and to update the
X library at the end in a single operation. If one of the
X members does not compile and dmake stops, then the user may
X fix the error and make again. dmake will not remake any of
X the targets whose object files have already been generated
X as long as none of their prerequisite files have been modi-
X fied as a result of the fix.
X
X When defining .SOURCE and .SOURCE.x targets the construct
X
X .SOURCE :
X .SOURCE : fred gery
X
X is equivalent to
X
X .SOURCE :- fred gery
X
X dmake correctly handles the UNIX Make variable VPATH. By
X definition VPATH contains a list of ':' separated direc-
X tories to search when looking for a target. dmake maps
X VPATH to the following special rule:
X
X .SOURCE :^ $(VPATH:s/:/ /)
X
X Which takes the value of VPATH and sets .SOURCE to the same
X set of directories as specified in VPATH.
X
X
X
Version 3.70 UW 33
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
PERCENT(%) RULES AND MAKING INFERENCES
X When dmake makes a target, the target's set of prerequisites
X (if any) must exist and the target must have a recipe which
X dmake can use to make it. If the makefile does not specify
X an explicit recipe for the target then dmake uses special
X rules to try to infer a recipe which it can use to make the
X target. Previous versions of Make perform this task by
X using rules that are defined by targets of the form
X .<suffix>.<suffix> and by using the .SUFFIXES list of suf-
X fixes. The exact workings of this mechanism were sometimes
X difficult to understand and often limiting in their useful-
X ness. Instead, dmake supports the concept of %-meta rules.
X The syntax and semantics of these rules differ from standard
X rule lines as follows:
X
X <%-target> [<attributes>] <ruleop> [<%-prerequisites>] [;<recipe>]
X
X where %-target is a target containing exactly a single `%'
X sign, attributes is a list (possibly empty) of attributes,
X ruleop is the standard set of rule operators, %-prere-
X quisites , if present, is a list of prerequisites containing
X zero or more `%' signs, and recipe, if present, is the first
X line of the recipe.
X
X The %-target defines a pattern against which a target whose
X recipe is being inferred gets matched. The pattern match
X goes as follows: all chars are matched exactly from left to
X right up to but not including the % sign in the pattern, %
X then matches the longest string from the actual target name
X not ending in the suffix given after the % sign in the pat-
X tern. Consider the following examples:
X
X %.c matches fred.c but not joe.c.Z
X dir/%.c matches dir/fred.c but not dd/fred.c
X fred/% matches fred/joe.c but not f/joe.c
X % matches anything
X
X In each case the part of the target name that matched the %
X sign is retained and is substituted for any % signs in the
X prerequisite list of the %-meta rule when the rule is
X selected during inference and dmake constructs the new
X dependency. As an example the following %-meta rules
X describe the following:
X
X %.c : %.y ; recipe...
X
X describes how to make any file ending in .c if a correspond-
X ing file ending in .y can be found.
X
X foo%.o : fee%.k ; recipe...
X
X is used to describe how to make fooxxxx.o from feexxxx.k.
X
X
X
Version 3.70 UW 34
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X %.a :; recipe...
X
X describes how to make a file whose suffix is .a without
X inferring any prerequisites.
X
X %.c : %.y yaccsrc/%.y ; recipe...
X
X is a short form for the construct:
X
X %.c : %.y ; recipe...
X %.c : yaccsrc/%.y ; recipe...
X
X ie. It is possible to specify the same recipe for two
X %-rules by giving more than one prerequisite in the prere-
X quisite list. A more interesting example is:
X
X % : RCS/%,v ; co $@
X
X which describes how to take any target and check it out of
X the RCS directory if the corresponding file exists in the
X RCS directory. The equivalent SCCS rule would be:
X
X % : s.% ; get $@
X
X
X The previous RCS example defines an infinite rule, because
X it says how to make anything from RCS/%,v, and anything also
X includes RCS/fred.c,v. To limit the size of the graph that
X results from such rules dmake uses the macro variable PREP
X (stands for % repetition). By default the value of this
X variable is 0, which says that no repetitions of a %-rule
X are to be generated. If it is set to something greater than
X 0, then that many repetitions of any infinite %-rule are
X allowed. If in the above example PREP was set to 1, then
X dmake would generate the dependency graph:
X
X % --> RCS/%,v --> RCS/RCS/%,v,v
X
X Where each link is assigned the same recipe as the first
X link. PREP should be used only in special cases, since it
X may result in a large increase in the number of possible
X prerequisites tested. dmake further assumes that any target
X that has no suffix can be made from a prerequisite that has
X at least one suffix.
X
X dmake supports dynamic prerequisite generation for prere-
X quisites of %-meta rules. This is best illustrated by an
X example. The RCS rule shown above can infer how to check
X out a file from a corresponding RCS file only if the target
X is a simple file name with no directory information. That
X is, the above rule can infer how to find RCS/fred.c,v from
X the target fred.c, but cannot infer how to find
X
X
X
Version 3.70 UW 35
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X srcdir/RCS/fred.c,v from srcdir/fred.c because the above
X rule will cause dmake to look for RCS/srcdir/fred.c,v; which
X does not exist (assume that srcdir has its own RCS directory
X as is the common case).
X
X A more versatile formulation of the above RCS check out rule
X is the following:
X
X % : $$(@:d)RCS/$$(@:f),v : co $@
X
X This rule uses the dynamic macro $@ to specify the prere-
X quisite to try to infer. During inference of this rule the
X macro $@ is set to the value of the target of the %-meta
X rule and the appropriate prerequisite is generated by
X extracting the directory portion of the target name (if
X any), appending the string RCS/ to it, and appending the
X target file name with a trailing ,v attached to the previous
X result.
X
X dmake can also infer indirect prerequisites. An inferred
X target can have a list of prerequisites added that will not
X show up in the value of $< but will show up in the value of
X $? and $&. Indirect prerequisites are specified in an
X inference rule by quoting the prerequisite with single
X quotes. For example, if you had the explicit dependency:
X
X fred.o : fred.c ; rule to make fred.o
X fred.o : local.h
X
X then this can be inferred for fred.o from the following
X inference rule:
X
X %.o : %.c 'local.h' ; rule to make a .o from a .c
X
X You may infer indirect prerequisites that are a function of
X the value of '%' in the current rule. The meta-rule:
X
X %.o : %.c '$(INC)/%.h' ; rule to make a .o from a .c
X
X infers an indirect prerequisite found in the INC directory
X whose name is the same as the expansion of $(INC), and the
X prerequisite name depends on the base name of the current
X target. The set of indirect prerequisites is attached to
X the meta rule in which they are specified and are inferred
X only if the rule is used to infer a recipe for a target.
X They do not play an active role in driving the inference
X algorithm. The construct:
X
X %.o : %.c %.f 'local.h'; recipe
X
X is equivalent to:
X
X
X
X
Version 3.70 UW 36
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X %.o : %.c 'local.h' : recipe
X %.o : %.f 'local.h' : recipe
X
X
X If any of the attributes .SETDIR, .EPILOG, .PROLOG, .SILENT,
X .USESHELL, .SWAP, .PRECIOUS, .LIBRARY, .NOSTATE and .IGNORE
X are given for a %-rule then when that rule is bound to a
X target as the result of an inference, the target's set of
X attributes is augmented by the attributes from the above set
X that are specified in the bound %-rule. Other attributes
X specified for %-meta rules are not inherited by the target.
X The .SETDIR attribute is treated in a special way. If the
X target already had a .SETDIR attribute set then dmake
X changes to that directory prior to performing the inference.
X During inference any .SETDIR attributes for the inferred
X prerequisite are honored. The directories must exist for a
X %-meta rule to be selected as a possible inference path. If
X the directories do not exist no error message is issued,
X instead the corresponding path in the inference graph is
X rejected.
X
X dmake also supports the old format special target
X .<suffix>.<suffix> by identifying any rules of this form and
X mapping them to the appropriate %-rule. So for example if
X an old makefile contains the construct:
X
X .c.o :; cc -c $< -o $@
X
X dmake maps this into the following %-rule:
X
X %.o : %.c; cc -c $< -o $@
X
X Furthermore, dmake understands several SYSV AUGMAKE special
X targets and maps them into corresponding %-meta rules.
X These transformation must be enabled by providing the -A
X flag on the command line or by setting the value of AUGMAKE
X to non-NULL. The construct
X
X .suff :; recipe
X
X gets mapped into:
X
X % : %.suff; recipe
X
X and the construct
X
X .c~.o :; recipe
X
X gets mapped into:
X
X %.o : s.%.c ; recipe
X
X
X
X
Version 3.70 UW 37
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X In general, a special target of the form .<str>~ is replaced
X by the %-rule construct s.%.<str>, thereby providing support
X for the syntax used by SYSV AUGMAKE for providing SCCS sup-
X port. When enabled, these mappings allow processing of
X existing SYSV makefiles without modifications.
X
X dmake bases all of its inferences on the inference graph
X constructed from the %-rules defined in the makefile. It
X knows exactly which targets can be made from which prere-
X quisites by making queries on the inference graph. For this
X reason .SUFFIXES is not needed and is completely ignored.
X
X For a %-meta rule to be inferred as the rule whose recipe
X will be used to make a target, the target's name must match
X the %-target pattern, and any inferred %-prerequisite must
X already exist or have an explicit recipe so that the prere-
X quisite can be made. Without transitive closure on the
X inference graph the above rule describes precisely when an
X inference match terminates the search. If transitive clo-
X sure is enabled (the usual case), and a prerequisite does
X not exist or cannot be made, then dmake invokes the infer-
X ence algorithm recursively on the prerequisite to see if
X there is some way the prerequisite can be manufactured.
X For, if the prerequisite can be made then the current target
X can also be made using the current %-meta rule. This means
X that there is no longer a need to give a rule for making a
X .o from a .y if you have already given a rule for making a
X .o from a .c and a .c from a .y. In such cases dmake can
X infer how to make the .o from the .y via the intermediary .c
X and will remove the .c when the .o is made. Transitive clo-
X sure can be disabled by giving the -T switch on the command
X line.
X
X A word of caution. dmake bases its transitive closure on
X the %-meta rule targets. When it performs transitive clo-
X sure it infers how to make a target from a prerequisite by
X performing a pattern match as if the potential prerequisite
X were a new target. The set of rules:
X
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
X will, by performing transitive closure, allow dmake to infer
X how to make a .o from a .y using a .c as an intermediate
X temporary file. Additionally it will be able to infer how
X to make a .y from an RCS file, as long as that RCS file is
X in the RCS directory and has a name which ends in .y,v. The
X transitivity computation is performed dynamically for each
X target that does not have a recipe. This has potential to
X be costly if the %-meta rules are not carefully specified.
X The .NOINFER attribute is used to mark a %-meta node as
X
X
X
Version 3.70 UW 38
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X being a final target during inference. Any node with this
X attribute set will not be used for subsequent inferences.
X As an example the node RCS/%,v is marked as a final node
X since we know that if the RCS file does not exist there
X likely is no other way to make it. Thus the standard
X startup makefile contains an entry similar to:
X .NOINFER : RCS/%,v
X Thereby indicating that the RCS file is the end of the
X inference chain.
X
X Whenever the inference algorithm determines that a target
X can be made from more than one prerequisite and the infer-
X ence chains for the two methods are the same length the
X algorithm reports an ambiguity and prints the ambiguous
X inference chains.
X
X dmake tries to remove intermediate files resulting from
X transitive closure if the file is not marked as being PRE-
X CIOUS, or the -u flag was not given on the command line, and
X if the inferred intermediate did not previously exist.
X Intermediate targets that existed prior to being made are
X never removed. This is in keeping with the philosophy that
X dmake should never remove things from the file system that
X it did not add. If the special target .REMOVE is defined
X and has a recipe then dmake constructs a list of the inter-
X mediate files to be removed and makes them prerequisites of
X .REMOVE. It then makes .REMOVE thereby removing the prere-
X quisites if the recipe of .REMOVE says to. Typically
X .REMOVE is defined in the startup file as:
X
X .REMOVE :; $(RM) $<
X
MAKING TARGETS
X In order to update a target dmake must execute a recipe.
X When a recipe needs to be executed it is first expanded so
X that any macros in the recipe text are expanded, and it is
X then either executed directly or passed to a shell. dmake
X supports two types of recipes. The regular recipes and
X group recipes.
X
X When a regular recipe is invoked dmake executes each line of
X the recipe separately using a new copy of a shell if a shell
X is required. Thus effects of commands do not generally per-
X sist across recipe lines. (e.g. cd requests in a recipe
X line do not carry over to the next recipe line) The decision
X on whether a shell is required to execute a command is based
X on the value of the macro SHELLMETAS or on the specification
X of '+' or .USESHELL for the current recipe or target respec-
X tively. If any character in the value of SHELLMETAS is
X found in the expanded recipe text-line or the use of a shell
X is requested explicitly via '+' or .USESHELL then the com-
X mand is executed using a shell, otherwise the command is
X
X
X
Version 3.70 UW 39
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X executed directly. The shell that is used for execution is
X given by the value of the macro SHELL. The flags that are
X passed to the shell are given by the value of SHELLFLAGS.
X Thus dmake constructs the command line:
X
X $(SHELL) $(SHELLFLAGS) $(expanded_recipe_command)
X
X Normally dmake writes the command line that it is about to
X invoke to standard output. If the .SILENT attribute is set
X for the target or for the recipe line (via @), then the
X recipe line is not echoed.
X
X Group recipe processing is similar to that of regular
X recipes, except that a shell is always invoked. The shell
X that is invoked is given by the value of the macro GROUP-
X SHELL, and its flags are taken from the value of the macro
X GROUPFLAGS. If a target has the .PROLOG attribute set then
X dmake prepends to the shell script the recipe associated
X with the special target .GROUPPROLOG, and if the attribute
X .EPILOG is set as well, then the recipe associated with the
X special target .GROUPEPILOG is appended to the script file.
X This facility can be used to always prepend a common header
X and common trailer to group recipes. Group recipes are
X echoed to standard output just like standard recipes, but
X are enclosed by lines beginning with [ and ].
X
X The recipe flags [+,-,%,@] are recognized at the start of a
X recipe line even if they appear in a macro. For example:
X
X SH = +
X all:
X $(SH)echo hi
X
X is completely equivalent to writing
X
X SH = +
X all:
X +echo hi
X
X
X The last step performed by dmake prior to running a recipe
X is to set the macro CMNDNAME to the name of the command to
X execute (determined by finding the first white-space ending
X token in the command line). It then sets the macro CMNDARGS
X to be the remainder of the line. dmake then expands the
X macro COMMAND which by default is set to
X
X COMMAND = $(CMNDNAME) $(CMNDARGS)
X
X The result of this final expansion is the command that will
X be executed. The reason for this expansion is to allow for
X a different interface to the argument passing facilities
X
X
X
Version 3.70 UW 40
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X (esp. under DOS) than that provided by dmake. You can for
X example define COMMAND to be
X
X COMMAND = $(CMNDNAME) @$(mktmp $(CMNDARGS))
X
X which dumps the arguments into a temporary file and runs the
X command
X
X $(CMNDNAME) @/tmp/ASAD23043
X
X which has a much shorter argument list. It is now up to the
X command to use the supplied argument as the source for all
X other arguments. As an optimization, if COMMAND is not
X defined dmake does not perform the above expansion. On sys-
X tems, such as UNIX, that handle long command lines this pro-
X vides a slight saving in processing the makefiles.
X
MAKING LIBRARIES
X Libraries are easy to maintain using dmake. A library is a
X file containing a collection of object files. Thus to make
X a library you simply specify it as a target with the
X .LIBRARY attribute set and specify its list of prere-
X quisites. The prerequisites should be the object members
X that are to go into the library. When dmake makes the
X library target it uses the .LIBRARY attribute to pass to the
X prerequisites the .LIBMEMBER attribute and the name of the
X library. This enables the file binding mechanism to look
X for the member in the library if an appropriate object file
X cannot be found. A small example best illustrates this.
X
X mylib.a .LIBRARY : mem1.o mem2.o mem3.o
X rules for making library...
X # remember to remove .o's when lib is made
X
X # equivalent to: '%.o : %.c ; ...'
X .c.o :; rules for making .o from .c say
X
X dmake will use the .c.o rule for making the library members
X if appropriate .c files can be found using the search rules.
X NOTE: this is not specific in any way to C programs, they
X are simply used as an example.
X
X dmake tries to handle the old library construct format in a
X sensible way. The construct lib(member.o) is separated and
X the lib portion is declared as a library target. The new
X target is defined with the .LIBRARY attribute set and the
X member.o portion of the construct is declared as a prere-
X quisite of the lib target. If the construct lib(member.o)
X appears as a prerequisite of a target in the makefile, that
X target has the new name of the lib assigned as its prere-
X quisite. Thus the following example:
X
X
X
X
Version 3.70 UW 41
X
X
X
X
DMAKE(p) Unsupported Free Software DMAKE(p)
X
X
X
X a.out : ml.a(a.o) ml.a(b.o); $(CC) -o $@ $<
X
X .c.o :; $(CC) -c $(CFLAGS) -o $@ $<
X %.a:
X ar rv $@ $<
X ranlib $@
X rm -rf $<
X
X constructs the following dependency graph.
X
X a.out : ml.a; $(CC) -o $@ $<
X ml.a .LIBRARY : a.o b.o
X
X %.o : %.c ; $(CC) -c $(CFLAGS) -o $@ $<
X %.a :
X ar rv $@ $<
X ranlib $@
X rm -rf $<
X
X and making a.out then works as expected.
X
X The same thing happens for any target of the form
X lib((entry)). These targets have an additional feature in
X that the entry target has the .SYMBOL attribute set automat-
X ically.
X
X NOTE: If the notion of entry points is supported by the
X archive and by dmake (currently not the case) then dmake
X will search the archive for the entry point and return not
X only the modification time of the member which defines the
X entry but also the name of the member file. This name will
X then replace entry and will be used for making the member
X file. Once bound to an archive member the .SYMBOL attribute
X is removed from the target. This feature is presently dis-
X abled as there is little standardization among archive for-
X mats, and we have yet to find a makefile utilizing this
X feature (possibly due to the fact that it is unimplemented
X in most versions of UNIX Make).
X
X Finally, when dmake looks for a library member it must first
X locate the library file. It does so by first looking for
X the library relative to the current directory and if it is
X not found it then looks relative to the current value of
X $(TMD). This allows commonly used libraries to be kept near
X the root of a source tree and to be easily found by dmake.
X
KEEP STATE
X dmake supports the keeping of state information for targets
X that it makes whenever the macro .KEEP_STATE is assigned a
X value. The value of the macro should be the name of a state
X file that will contain the state information. If state
X keeping is enabled then each target that does not poses the
SHAR_EOF
true || echo 'restore of dmake/man/dmake.nc failed'
fi
echo 'End of part 14, continue with part 15'
echo 15 > _shar_seq_.tmp
exit 0
exit 0 # Just in case...
--
Kent Landfield INTERNET: kent@sparky.IMD.Sterling.COM
Sterling Software, IMD UUCP: uunet!sparky!kent
Phone: (402) 291-8300 FAX: (402) 291-4362
Please send comp.sources.misc-related mail to kent@uunet.uu.net.