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Newsgroups: comp.sources.misc
X-UNIX-From: dvadura@watdragon.waterloo.edu
subject: v15i069: dmake version 3.6 (part 17/25)
from: Dennis Vadura <dvadura@watdragon.waterloo.edu>
Sender: allbery@uunet.UU.NET (Brandon S. Allbery - comp.sources.misc)
Posting-number: Volume 15, Issue 69
Submitted-by: Dennis Vadura <dvadura@watdragon.waterloo.edu>
Archive-name: dmake-3.6/part17
#!/bin/sh
# this is part 17 of a multipart archive
# do not concatenate these parts, unpack them in order with /bin/sh
# file man/dmake.nc continued
#
CurArch=17
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.nc"
sed 's/^X//' << 'SHAR_EOF' >> man/dmake.nc
X it is redundant as a shell is already being used to run the
X recipe. See the MAKING TARGETS section for a description of
X how dmake invokes recipes. Here is an example of a group
X recipe:
X
X target :
X [
X first recipe line
X second recipe line
X all of these recipe lines are fed to a
X single copy of a shell for execution.
X ]
X
X
X
X
XVersion 3.50 UW 18
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
XTEXT DIVERSIONS
X dmake supports the notion of text diversions. If a recipe
X line contains the macro expression
X
X $(mktmp[,name_modifier] data)
X
X then all text contained in the data expression is expanded
X and is written to a new temporary file. The name of that
X file is then returned as the value of the macro expansion
X and is substituted for the text of the macro expression if
X no name_modifier is present.
X
X data can be any text and must be separated from the 'mktmp'
X portion of the macro name by white-space. The only restric-
X tion on the data text is that it must contain an balanced
X number of parentheses of the same kind as are used to ini-
X tiate the $(mktmp ...) expression. For example:
X
X $(mktmp $(XXX))
X
X is legal and works as expected, but:
X
X $(mktmp text (to dump to file)
X
X is not legal. You can achieve what you wish by either
X defining a macro that expands to '(' or by using {} in the
X macro expression; like this:
X
X ${mktmp text (to dump to file}
X
X which works as expected. Since the temporary file is opened
X when the macro containg the text diversion expression is
X expanded, diversions may now be nested and any diversions
X that are created as part of ':=' macro expansions persist
X for the duration of the dmake run. The diversion text may
X contain the same escape codes as those described in the MAC-
X ROS section. Thus if the data text is to contain new lines
X they must be inserted using the \n escape sequence. For
X example the expression:
X
X all:
X cat $(mktmp this is a\n\
X test of the text diversion\n)
X
X is replaced by:
X
X cat /tmp/mk12294AA
X
X where the temporary file contains two lines both of which
X are terminated by a new-line. If the data text spans multi-
X ple lines in the makefile then each line must be continued
X via the use of a \. A second more illustrative example
X
X
X
XVersion 3.50 UW 19
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
X generates a response file to an MSDOS link command:
X
X OBJ = fred.obj mary.obj joe.obj
X all : $(OBJ)
X link @$(mktmp $(^:t"+\n")\n)
X
X The result of making `all' in the second example is the com-
X mand:
X
X link @/tmp/mk02394AA
X
X where the temporary file contains:
X
X fred.obj+
X mary.obj+
X joe.obj
X
X The last line of the file is terminated by a new-line which
X is inserted due to the \n found at the end of the data
X string.
X
X If the optional name_modifier is supplied in the diversion
X expression then the returned value of the expression is the
X expanded value of name_modifier. Together with the special
X macros TMPFILE and USESHELL this can be used to alter the
X name of the temporary file returned as the result of the
X $(mktmp ...) expansion.
X
X Under MS-DOS text diversions may be a problem. Many DOS
X tools require that path names which contain directories use
X the \ character to delimit the directories. Some users how-
X ever wish to use the '/' to delimit pathnames on their sys-
X tem and use environments that allow them to do so. These
X environments usually accept the \ delimited path names as
X well. In order to allow the user the most flexibility dmake
X defines three macros that can be used when text diversion
X file names are being placed into the recipe text to be exe-
X cuted. The macro TMPFILE contains the name of the most
X recently opened temporary file, and the macro, USESHELL, is
X set to "yes" if the current recipe is forced to use a shell
X via the .USESHELL or '+' directives, otherwise its value is
X "no". In the absence of a name_modifier in the diversion
X expression the result of expanding the diversion expression
X is the value of TMPFILE. The dmake startup files define the
X macro DIVFILE whose value is either the value of TMPFILE or
X the value of TMPFILE editted to replace any '/' characters
X to the appropriate value based on the current shell and
X whether it will be used to execute the recipe.
X
X Previous versions of dmake defined text diversions using <+,
X +> strings, where <+ started a text diversion and +> ter-
X minated one. dmake is backward compatible with this
X
X
X
XVersion 3.50 UW 20
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
X construct if the <+ and +> appear literally on the same
X recipe line or in the same macro value string. In such
X instances the expression:
X
X <+data text+>
X
X is mapped to:
X
X $(mktmp data text)
X
X which is fully output compatible with the earlier construct.
X <+, +> constructs whose text spans multiple lines must be
X converted by hand to use $(mktmp ...).
X
X If the environment variable TMPDIR is defined then the tem-
X porary file is placed into the directory specified by that
X variable. A makefile can modify the location of temporary
X files by defining a macro named TMPDIR and exporting it
X using the .EXPORT special target.
X
XSPECIAL TARGETS
X This section describes the special targets that are recog-
X nized by dmake. Some are affected by attributes and others
X are not.
X
X .ERROR If defined then the recipe associated with
X this target is executed whenever an error con-
X dition is detected by dmake. All attributes
X that can be used with any other target may be
X used with this target. Any prerequisites of
X this target will be brought up to date during
X it's processing. NOTE: errors will be
X ignored while making this target, in extreme
X cases this may cause some problems.
X
X .EXPORT All prerequisites associated with this target
X are assumed to correspond to macro names and
X they and their values are exported to the
X environment as environment strings at the
X point in the makefile at which this target
X appears. Any attributes specified with this
X target are ignored. Only macros which have
X been assigned a value in the makefile prior to
X the export directive are exported, macros as
X yet undefined are not exported.
X
X .IMPORT Prerequisite names specified for this target
X are searched for in the environment and
X defined as macros with their value taken from
X the environment. If the name cannot be found
X in the environment an error message is issued.
X .IMPORT accepts the .IGNORE attribute. When
X
X
X
XVersion 3.50 UW 21
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
X given, it causes dmake to ignore the above
X error. See the MACROS section for a descrip-
X tion of the processing of imported macro
X values.
X
X .INCLUDE Parse another makefile just as if it had been
X located at the point of the .INCLUDE in the
X current makefile. The list of prerequisites
X gives the list of makefiles to try to read.
X If the list contains multiple makefiles then
X they are read in order from left to right.
X The following search rules are used when try-
X ing to locate the file. If the filename is
X surrounded by " or just by itself then it is
X searched for in the current directory. If it
X is not found it is then searched for in each
X of the directories specified for the .INCLU-
X DEDIRS special target. If the file name is
X surrounded by < and >, (ie.
X <my_spiffy_new_makefile>) then it is searched
X for only in the directories given by the
X .INCLUDEDIRS special target. In both cases if
X the file name is a fully qualified name start-
X ing at the root of the file system then it is
X only searched for once, and the .INCLUDEDIRS
X list is ignored. .INCLUDE accepts the .IGNORE
X and .SETDIR attributes. If .IGNORE attribute
X is given and the file cannot be found then
X dmake continues processing, otherwise an error
X message is generated. The .SETDIR attribute
X causes dmake to change directories to the
X specified directory prior to attempting the
X include operation.
X
X .INCLUDEDIRS The list of prerequisites specified for this
X target defines the set of directories to
X search when trying to include a makefile.
X
X .MAKEFILES The list of prerequisites is the set of files
X to try to read as the default makefile. By
X default this target is defined as:
X
X .MAKEFILES : makefile.mk Makefile
X makefile
X
X
X .SOURCE The prerequisite list of this target defines a
X set of directories to check when trying to
X locate a target file name. See the section on
X BINDING of targets for more information.
X
X
X
X
X
XVersion 3.50 UW 22
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
X .SOURCE.suff The same as .SOURCE, except that the
X .SOURCE.suff list is searched first when try-
X ing to locate a file matching the a target
X whose name ends in the suffix .suff.
X
X .REMOVE The recipe of this target is used whenever
X dmake needs to remove intermediate targets
X that were made but do not need to be kept
X around. Such targets result from the applica-
X tion of transitive closure on the dependency
X graph.
X
X In addition to the special targets above, several other
X forms of targets are recognized and are considered special,
X their exact form and use is defined in the sections that
X follow.
X
XSPECIAL MACROS
X dmake defines a number of special macros. They are divided
X into three classes: control macros, run-time macros, and
X function macros. The control macros are used by dmake to
X configure it's actions, and are the preferred method of
X doing so. In the case when a control macro has the same
X function as a special target or attribute they share the
X same name as the special target or attribute. The run-time
X macros are defined when dmake makes targets and may be used
X by the user inside recipes. The function macros provide
X higher level functions dealing with macro expansion and
X diversion file processing.
X
XCONTROL MACROS
X To use the control macros simply assign them a value just
X like any other macro. The control macros are divided into
X three groups: string valued macros, character valued macros,
X and boolean valued macros.
X
X The following are all of the string valued macros. This
X list is divided into two groups. The first group gives the
X string valued macros that are defined internally and cannot
X be directly set by the user.
X
X DIRBRKSTR Contains the string of chars used to terminate
X the name of a directory in a pathname. Under
X UNIX it's value is "/", under MSDOS it's value
X is "/\:".
X
X INCDEPTH This macro's value is a string of digits
X representing the current depth of makefile
X inclusion. In the first makefile level this
X value is zero.
X
X
X
X
X
XVersion 3.50 UW 23
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
X MFLAGS Is the list of flags that were given on the
X command line including a leading switch char-
X acter. The -f flag is not included in this
X list.
X
X MAKECMD Is the name with which dmake was invoked.
X
X MAKEDIR Is the full path to the initial directory in
X which dmake was invoked.
X
X MAKEFILE Contains the string "-f makefile" where,
X makefile is the name of initial user makefile
X that was first read.
X
X MAKEFLAGS Is the same as $(MFLAGS) but has no leading
X switch character. (ie. MFLAGS = -$(MAKEFLAGS))
X
X MAKEMACROS Contains the complete list of macro expres-
X sions that were specified on the command line.
X
X MAKETARGETS Contains the name(s) of the target(s), if any,
X that were specified on the command line.
X
X MAXPROCESSLIMIT
X Is a numeric string representing the maximum
X number of processes that dmake can use when
X making targets using parallel mode.
X
X NULL Is permanently defined to be the NULL string.
X This is useful when comparing a conditional
X expression to an NULL value.
X
X PWD Is the full path to the current directory in
X which make is executing.
X
X TMPFILE Is set to the name of the most recent tem-
X porary file opened by dmake. Temporary files
X are used for text diversions and for group
X recipe processing.
X
X TMD Stands for "To Make Dir", and is the path from
X the present directory (value of $(PWD)) to the
X directory that dmake was started up in (value
X of $(MAKEDIR)). This macro is modified when
X .SETDIR attributes are processed.
X
X USESHELL The value of this macro is set to "yes" if the
X current recipe is forced to use a shell for
X its execution via the .USESHELL or '+' direc-
X tives, its value is "no" otherwise.
X
X
X
X
X
XVersion 3.50 UW 24
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
X The second group of string valued macros control dmake
X behavior and may be set by the user.
X
X .SETDIR If this macro is assigned a value then dmake
X will change to the directory given by that
X value before making any targets. This macro
X is equivalent to the .SETDIR attribute.
X Thus the two lines:
X
X .SETDIR=fred/hello :
X
X .SETDIR := fred/hello
X
X are completely equivalent. The difference
X being that the first is processed as a rule
X definition and the other as a macro.
X
X AUGMAKE If set to a non NULL value will enable the
X transformation of special meta targets to
X support special AUGMAKE inferences.
X
X DIRSEPSTR Contains the string that is used to separate
X directory components when path names are
X constructed. It is defined with a default
X value at startup.
X
X DIVFILE Is defined in the startup file and gives the
X name that should be used for the diversion
X file name when specified as the name modif-
X ier in $(mktmp ...) expansions, see the TEXT
X DIVERSION section for details.
X
X GROUPFLAGS This macro gives the set of flags to pass to
X the shell when invoking it to execute a
X group recipe. The value of the macro is the
X list of flags with a leading switch indica-
X tor. (ie. `-' under UNIX)
X
X GROUPSHELL This macro defines the full path to the exe-
X cutable image to be used as the shell when
X processing group recipes. This macro must
X be defined if group recipes are used. It is
X assigned a default value in the startup
X makefile. Under UNIX this value is /bin/sh.
X
X GROUPSUFFIX If defined, this macro gives the string to
X use as a suffix when creating group recipe
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
X
X
XVersion 3.50 UW 25
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
X GROUPSHELL, then this suffix must be set to
X .bat in order for group recipes to function
X correctly.
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 it's initial value.
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 it's
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
X
X
XVersion 3.50 UW 26
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
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 it's
X correct execution. In such instances a
X shell is used to invoke the recipe line. If
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. On UNIX it's value is '-', on
X MSDOS it's value may be '/' or '-'. The macro is internally
X defined and is not user setable. The MSDOS version of dmake
X attempts to first extract SWITCHAR from an environment vari-
X able of the same name. If that fails it then attempts to
X use the undocumented getswitchar interrupt call, and returns
X the result of that. Thus under MSDOS version 4.0 you must
X set the value of the environment macro SWITCHAR to '/' to
X obtain predictable behaviour.
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, .PRECIOUS, .PROLOG,
X .SEQUENTIAL, .SILENT, .SWAP, and .USESHELL. Assigning any
X of these a non NULL value will globally set the correspond-
X ing attribute to on.
X
XRUN_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
X
X
X
XVersion 3.50 UW 27
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
X specified 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, $$ expands to $, {{ expands to {, }} expands to },
X and the strings <+ and +> are recognized as respectively
X starting and terminating a text diversion when they appear
X literally together in the same input line.
X
X The difference between $? and $^ can best be illustrated by
X an example, consider:
X
X fred.out : joe amy hello
X rules for making fred
X
X fred.out : my.c your.h his.h her.h # more prerequisites
X
X Assume joe, amy, and my.c are newer then fred.out. When
X dmake executes the recipe for making fred.out the values of
X the following macros will be:
X
X $@ --> fred.out
X $* --> fred
X $? --> joe amy my.c # note the difference between $? and $^
X $^ --> joe amy
X $< --> joe amy hello
X $& --> joe amy hello my.c your.h his.h her.h
X
X
XFUNCTION MACROS
X Only one function macro is defined at this time. The
X $(mktmp ...) construct can be used to create a temporary
X file containing data and returns the name of that file as
X it's result. See the TEXT DIVERSION section for details on
X its use. Temporary files created using this macro persist
X for the duration of the dmake run if processed as part of a
X macro assignment operation, or until an associated target's
X recipe is fully completed at which time the temporary file
X is removed. NOTE: Specifying '-v' on the command line
X causes all temporary files to be retained when dmake exits.
X
X
X
X
X
X
XVersion 3.50 UW 28
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
XDYNAMIC PREREQUISITES
X dmake looks for prerequisites whose names contain macro
X expansions during target processing. Any such prerequisites
X are expanded and the result of the expansion is used as the
X prerequisite name. As an example the line:
X
X fred : $$@.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 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
XBINDING 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 it's 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
X
X
XVersion 3.50 UW 29
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
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 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
X
X
XVersion 3.50 UW 30
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
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
XPERCENT(%) RULES AND MAKING INFERENCES
X When dmake makes a target it's set of prerequisites (if any)
X must exist and the target must have a recipe which dmake can
X use to make it. If the makefile does not specify an expli-
X cit recipe for the target then dmake uses special rules to
X try to infer a recipe which it can use to make the target.
X Previous versions of Make perform this task by using rules
X that are defined by targets of the form .<suffix>.<suffix>
X and by using the .SUFFIXES list of suffixes. The exact
X workings of this mechanism were sometimes difficult to
X understand and often limiting in their usefulness. Instead,
X dmake supports the concept of %-meta rules. The syntax and
X semantics of these rules differ from standard rule lines as
X 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
X
X
XVersion 3.50 UW 31
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
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 depen-
X dency specified by the %-meta rule for the actual target.
X As an example the following %-meta rules describe the fol-
X lowing:
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 %.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
X
X
XVersion 3.50 UW 32
X
X
X
X
XDMAKE(p) Unsupported Software DMAKE(p)
X
X
X
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.
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 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 it's own RCS direc-
X tory 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
SHAR_EOF
echo "End of part 17"
echo "File man/dmake.nc is continued in part 18"
echo "18" > s2_seq_.tmp
exit 0
