SMAKE(1)

NAME
smake - maintain, update, and regenerate programs

SYNOPSIS
smake [ options ] [ -f makefilename ] [ target1...targetn ]

DESCRIPTION
Smake executes command sequences based on relations of modification dates of files. The command sequences are taken from a set of rules found in a makefile or in the set of implicit rules. The argument target is typically a program that is to be built from the known rules.

If no -f option is present, smake looks for SMakefile then for Makefile and then for makefile in the named order. If in POSIX mode, smake looks for makefile, Makefile and then for SMakefile.

If no target is specified on the command line, smake uses the first regular target that could be found in makefilename and that does not start with a dot ('.') letter combination.

If a target has no explicit entry in the makefile smake tries to use implicit rules or the .DEFAULT rule.

Unlike most other make programs, smake propagates all command line macros to sub makes. This is a big advantage with hierarchical makefile systems. Propagation is done in a POSIX compliant way using the MAKEFLAGS= environment.

Unlike other make programs, smake includes a set of automake features that allow to implement portable, layered, object oriented makefiles.

OPTIONS

-C dir
    Change the working directory to dir before starting work.

-e  Environment variables override macro definition in Makefile(s).

-i  Ignore error codes returned by commands that are called from rules. This is equivalent to having the special target .IGNORE without dependencies inside a makefile.

-k  Ignore errors by aborting work on the current target and continuing the work on other targets that do not depend on the failed target.

-N  Continue if a named dependency does not exist and no related source could be found. Smake by default aborts on this condition, but it seems that traditional UNIX make programs ignore this condition for unknown reason.

-n  Don't make - only say what to do. This prints the commands that would be executed on standard output. Lines with a plus sign ('+') will be executed in any case. Even those lines that have an at sign ('@') will be printed to standard output. If a command line contains the macro $(MAKE) or ${MAKE} this command line is executed even if there is no plus sign ('+').

-p  Print the complete set of macro and target definitions on standard output.

-q  Question mode. Exit code is 0 if the target is up to date. In all other cases, the exit code is 1. Lines with a plus sign ('+') will be executed in any case.

-r  Turn off internal rules. Do not use the built in rules and do not read the files ./defaults.smk and /opt/schily/lib/defaults.smk

-S  Undo the effect of the -k option and terminate smake if an error occurs while updating targets.

-s  Be silent. (Do not print command lines or touch messages on standard output before they are executed.) This is equivalent to having the special target .SILENT without dependencies inside a makefile.

-t  Touch objects instead of executing the defined commands. This brings a target up to date by simply setting the modification time of the targets instead of performing the their rules. Warning: This can be dangerous when files are maintained by more than one person. Targets that do not have a command associated are not touched. The command lines that are associated with a target are not executed. Lines with a plus sign ('+') will be executed in any case.

-w  Don't print warning messages.

-W  Print extra debug messages and warning messages.

-WW Print even more extra debug messages and warning messages.

-D  Display Makefiles as they are read in. This allows to debug the effective makefile when the makefiles use include statements.

-DD Display Makefiles and internal rules as they are read in. This is the same as specifying -D but smake starts to print the effective makefile when reading the internal definitions. If -DDD is specified, the printout includes even the definitions of the environment variables as make macros.

-d  Print the reason why a target has to be rebuilt. Also turns off external and internal silent flag. This special feature allows to write makefiles that usually suppress the printing of commands line (using a '@' at the start of a command line) as in debug mode smake undoes the effect of the '@' character.

-dd Print additional debugging messages. This includes the messages from the -d flag and additional messages that allow to trace the execution of the various rules. If more 'd' characters are added (e.g. -dddd) the verbose level for tracing is enhanced.

-xM Print the make file include dependency list. This options allows to trace complex makefiles that make heavy use of the include statement.

-xd Print extended debug messages. This is only useful, if you have internal knowledge to smake itself and want to do heavy debugging.

-probj
    Print the whole object tree. This is only useful, if you have internal knowledge to smake itself and want to do heavy debugging.

-help
    Prints a short summary of the smake options and exists.

-version
    Prints the smake version number string and exists.

-posix
    Force smake to go into POSIX mode. This is equivalent to having the special target .POSIX inside a makefile.

    See the description of the special target .POSIX for more information.

-f makefilename, mf=makefilename, mf= makefilename
    Specifies the Makefile.

macro=value
    Set a macro. A macro definition on command line overrides any other macro definition.

Options, command line macros and target name may be intermixed. Smake will always first evaluate all options then all command line macros and then will start building the targets. With smake it is not possible to first make one target, then set a command line macro and then make the next target with different macro values, POSIX does not specify the behavior in this case anyway.

OPERANDS
The following operands are supported:

target
    any number of target names. The targets are build in the order of occurence.

macro=value
    A macro definition. Macro definitions from the command line overwrite regular macro definitions in makefiles or taken from the environment.

All macro definitions are evaluated before any target it build.

BASICS

Smake maintains the dependency of a group of files by building a dependency tree of the targets (derived files) and the files that are the prerequisites of the targets (called the sources or the dependency list of files). A makefile contains a description of the relations of the targets and the prerequisites and the commands that should be executed to make the target up to date.

	foo : main.o lex.o parse.o
	main.o: main.c main.h

The file foo depends on the files main.o lex.o and parse.o while main.o depends on main.c and main.h. This example describes a project in the C-programming language, but it is possible to maintain any project that depends on the modification time of the related files.

Smake considers a file up to date if it has been modified after the files it depends on (its prerequisites) and all files it depends on are recursively up to date too. If a file does not exit, it is considered to be out of date. The targets are processed in the order they appear in the dependency list.

For example, if main.o is newer than foo, then it is assumed that foo is not up to date. If main.c is newer than main.o, then it is assumed that both, main.o and foo are not up to date.

Smake updates all targets based on rules. A rule specifies a target and its prerequisites and defines a set of commands that allow to create an up to date target from its prerequisites.

If the target and its prerequisites are named explicitely, the rule is called an explicit rule. If the target and its prerequisites are named in an abstract way, the rule is called an implicit rule or an inference rule.

If smake is called to update a target, it first checks if an explicit rule for this target can be found. If there is no explicit rule for this target, then smake looks for an implicit rule. It checks the following methods of specifying an implicit rule until a suitable rule is found. Each method is described in section Makefile Format below or in the section Implicit Rules.

•   Pattern matching rules from a user supplied makefile.

•   Suffix rules, either from a user supplied makefile or from the set of builtin rules.

•   Simple suffix rules, either from a user supplied makefile or from the set of builtin rules.

•   SCCS retrieval. If smake finds a more recent SCCS history file, it tries to retrieve the most recent version from the SCCS history. See the description of the .SCCS_GET special target.

•   The rule from the .DEFAULT target entry, if such an entry exists in a makefile.

A limited set of built in rules is compiled into smake. A more complete set is read from the file ./defaults.smk or /opt/schily/lib/defaults.smk.

Makefile Format

Smake reads its rules from a file named SMakefile, Makefile or makefile in the current directory and checks for the files in the named order. If in POSIX mode, smake looks for makefile, Makefile and then for SMakefile. If a different makefile is specified with the -f option, smake reads from this file. In case that no makefile was specified with the -f option, it is not an error if no makefile exists. In this case smake only uses the built in rules. The term makefile is used for any user supplied file that contains rules for the make utility.

A makefile contains rules, macro definitions, special make directives and comments. A rule may either be a target rule (explicit rule) or an implicit rule. Smake itself contains or loads a number of built in implicit rules which are not used if the -r option is used. The user specified makefile defines additional explicit and implicit rules and macros. If a macro is defined more than once, the last definition is used. If a target rule is defined more than once, the dependency list is the sum of all dependency lists and the set of commands is the set of commands from the last specification. A back slash ('\') at the end of a line indicates that this line is to be continued on the next line. An escaped newline is replaced by a single space character and the white space at the beginning of the next line is removed. A comment starts with a hash mark ('#') and ends if an un-escaped new line is found.

  Command Execution

Command lines associated with rules are sequentially executed line by line in an own process or shell. All commands may use constructs supported by the standard shell (/bin/sh). POSIX shell constructs are permitted as long as the local shell supports them. Command lines may have prefixes that are interpreted by smake before the rest of the command line is executed or passed to the shell. All characters from the list below that immediately follow the TAB character are interpreted by smake. The first non-blank character that is not from the list below is the first character passed to the shell. The following prefixes are implemented:

-   If the character '-' is amongst the prefix characters or of the -i option has been specified or the special target .IGNORE has been specified with no dependencies or with the current target in the list of dependencies, the exit code from the command line is ignored.

+   If the character '+' is amongst the prefix characters, the command line is executed even if one of the options -n, -q or -t was specified.

@   If the character '@' is amongst the prefix characters or of the -s option has been specified or the special target .SILENT has been specified with no dependencies or with the current target in the list of dependencies, the command line is not printed before it is executed.

?   Reserved for future use (currently ignored).

!   Reserved for future use (currently ignored).

Typical UNIX systems are fast with calling the shell. Some operating systems (like e.g. win32) however are slow with creating processes. As calling a command via the shell results in creating an additional process, command execution via the shell causes unneeded overhead for simple commands. To speed up command execution, smake tries to avoid calling commands via the shell when no shell meta character appears on the commandline. As commandlines used in makefiles frequently look like:

@echo message; cc ...

smake avoids to call a shell in such cases by executing simple echo commands inline in case they are at the beginning of a command. A simple echo command is a command without I/O redirection and without shell variable expansion.

If the environment FORCE_SHELL is present or the special target .FORCE_SHELL: has been defined, smake does not try to optimize command execution and calls all commands via the shell. If the SHELL special macro is used to define an alternate shell that is based on a different set of shell meta characters than the meta characters used by the POSIX shell:

    # | = ^ ( ) ; & < > * ? [ ] : $ ` ' " \ \n

it is recommended to define the special target .FORCE_SHELL: in addition.

  Target rules

A target rule looks this way:

    target ... [:|::] [dependency] ... [; command] ...
    [<tab> command]
    ...

The first line may not start with a TAB character. It starts with a target name or a white space separated list of target names, in both cases followed by colon as a target separator (':') or by a double colon ('::'). The colon may be followed by a dependency name or a white space separated list of dependency names. The double colon allows to specify alternate dependency lists and commands for the same target. The dependency list may be followed by a semicolon (';') and a Bourne shell command. There may be additional lines with Bourne shell commands, all starting with a TAB. The first line that does not start with a TAB starts another definition.

Bourne shell commands may be continued over more than one line if the new line is escaped with a back slash. The next line must also start with a TAB character.

  Make directives

export macro ...
    The list of macros that follows the export directive is exported in the list of environment variables. If an environment variable with the same name already exists, it's value is replaced by the current value of the related make macro. An empty list of macro names is not considered an error. If the PATH macro is in the list of parameters, the path search of the current smake process is also affected. If the SHELL macro is in the list of parameters, it is ignored and the previous SHELL environment is kept.

include filename ...
    Reading and parsing makefiles is temporarily continued with the list of the file name parameters to the include directive. If one or more file names from the parameter list contains make macro expressions, the macro expressions are evaluated before the file names are used. A single make macro may contain a list of include file names. If smake knows rules to make the files to include, smake will evaluate the related rules before doing the include. Include directives may be nested as long as there are unsued file descriptors. An empty list of filenames is not considered an error. If one or more files from the parameter list do not exist, smake aborts.

-include filename ...
    The -include directive is implemented similar to the include directive, except that a nonexistent file is not considered to be an error.

readonly macro ...
    Mark the list of macros in the parameter list as readonly. This prevents further modification of the content of the related macros. An empty list of macro names is not considered an error.

unexport macro ...
    The list of macros that follows the unexport directive is removed from the list of environment variables. An empty list of macro names is not considered an error. If the PATH macro is in the list of parameters, the path search of the current smake process is also affected. If the SHELL macro is in the list of parameters, it is ignored and the previous SHELL environment is kept.

Automake Features

Smake implements automake features that help to write highly portable makefile systems. The automake features are implemented with a set of special purpose macros and by special rules that help to extend the functionality and automated adaptivity of smake.

  Automake special purpose macros

The special purpose macros that have names that match MAKE_* (see section Special Macros) are part of the automake features of smake. The related special macros are set up by smake to contain values that have been retrieved from the results of the uname(2), sysinfo(2) or sysctl(2) system calls. The values for these macros may however be overwritten from a makefile or from a command line macro definition.

  Automake special targets

The special target .INCLUDE_FAILED allows to define a rule that is evaluated in case that an include files does not exist and could not be made from other rules. As the asociated command for this target is typically a shell script, the shell script can be written to create fall back rules in a platform independent way.

Search Rules For Files

In many cases, it is desirable to hold object files in a special directory which is different from the directory where the source files are located. For this reason, smake allows to specify a directory where all targets are placed in case they are a result of an implicit rule. Add

.OBJDIR: object_directory

to the makefile to activate this smake feature. If a makefile uses this feature, it must either explicitely use the right file names (including the object directory) or use dynamic macros that are automatically updated to include the path of the object directory. If smake uses file name searching, the dynamic macros $<, $0, $n, $r1, $^, and $? are updated to reflect the actual path of the source or object directory.

A line of the form:

.SEARCHLIST: source_directory_1 object_directory_1 ...

that contains pairs of source and corresponding object directory names, will cause smake not only to search for files in the current directory and in the directory which is pointed to by .OBJDIR, but also in the directories from .SEARCHLIST:. Smake first looks in the current directory, then in the directory pointed to by .OBJDIR and then in the directories from .SEARCHLIST:.

If a source could be found in a specific source directory of the list of source and object directories, the targets will only be looked for in the corresponding object directory. A result of a source, which is found in any of the source-directories of the .SEARCHLIST: is placed into the corresponding object-directory.

A line in the form:

.OBJSEARCH:value

Where value may be one of src, obj, all. causes smake to look for left-hand-sides of rules in only the source-directories, the object-directories or both. The default value for .OBJSEARCH: is: all. That causes smake to search for results in object-directories and source-directories.

If no .SEARCHLIST target exists, but a VPATH= macro is found, smake transforms the content of the VPATH= macro into a form suitable for .SEARCHLIST:. This is done by putting each VPATH= entry twice into the .SEARCHLIST:. Please report problems with this solution.

Macros

  Macro Definitions
Macros are defined by a line in the form:

macroname= value

The value assigned to the macro contains all characters after the equal sign up to a comment character ('#') or an unescaped newline. Any blank characters that directly follow the equal sign are ignored.

An alternate macro definitions use the form:

macroname += value

to append value to the current definition for macroname. Note that there needs to be white space before the '+=' as smake allows macro names like C++.

A macro definition that uses the form:

macroname:= value

will evaluate the right side of the assignment when the line is read by the parser. Note that SunPro make uses := for a different incompatible purpose. A makefile that uses := is non-portable.

A macro definition that uses the form:

macroname:sh= command

will call command and define the macro value to be the output of command when the line is read by the parser.

  Macro References

Macros may be referenced by either: $(macroname) or ${macroname}. The parentheses or braces are optional for a macro with a single character name.

Macro definitions and macro references can appear anywhere in the makefile. Macro references are expanded under the following circumstances:

•   Macros in target lines are evaluated when the target line is read by the parser.

•   Macros in command lines for rules are evaluated when the command is executed.

•   Macros in the string before ':', '::', '=' or '+=' (names for target or macro definitions) are evaluated when the target line is read by the parser.

•   Macro references after the equal sign in a macro definition are not evaluated until the defined macro itself is used in a rule or a command or to the left of the equal sign from a macro definition.

  Macro Substitution

Macro references may be used to substitute macro values. There are different methods for macro substitution.

  Suffix Replacement Macro References

A macro reference in the following form:

    $(name:subst1=subst2)

is used to replace the suffix or word subst1 in the value of the macro name by subst2. Words are separated by space or tab characters.

  Pattern Replacement Macro References

A macro reference in the following form:

    $(name:op%os=np%ns)

is used to replace prefixes and suffixes in words. In this case, op is the old prefix, os is the old suffix, np is the new prefix and ns is the new suffix. The strings op, os, np and ns may all be empty strings. The pattern % matches a string of zero or more characters. The matched pattern is carried forward to the replacement target. For example:

OBJECT=foo.o
SCCS_HISTFILE=$(OBJECT:%.o=SCCS/s.%.c)

replaces foo.o by SCCS/s.foo.c when the macro $(SCCS_HISTFILE) is referenced.

  Shell Replacement Macro References

A macro reference in the following form:

    $(name:sh)

will interpret the content of the macro name as a shell command line, call the shell with the content of the macro and return the output of the called command.

Special Targets

.DEFAULT:
    If a target is considered to be out of date and no other rule applies to this target, smake executes the commands from this special target. The .DEFAULT target may not have a dependency list.

.DONE:
    If this special target is present, smake executes the commands after all targets have been processed. The .DONE target is also executed if a failure occurs and no .FAILED target is present. The .DONE target may not have a dependency list.

.FAILED:
    If this special target is present and an error occurred, smake executes the commands instead of the the commands of the .DONE target after all targets have been processed. The .FAILED target may not have a dependency list.

.FORCE_SHELL:
    If this special target is present, smake executes all commands via the shell instead of trying to optimize command execution for simple commands.

.GET_POSIX:
    Reserved for future use.

.IGNORE:
    Ignore errors. When this special target is present and has no dependencies, smake will ignore errors from commands. Specifying .IGNORE: without dependencies is equivalent to using the -i option. If .IGNORE: has dependencies and the current target is in the list of dependencies of .IGNORE: the exit code for the related commands is ignored.

.INCLUDE_FAILED:
    This special target implements automake features for object oriented layered makefiles. If this target is present, smake executes the commands for this target in case that a make file could not be included and there was no other explicit or implicit rule that did create the the missing make include file. The .INCLUDE_FAILED target may not have a dependency list. When the commands for the target .INCLUDE_FAILED are called, the dependency list of the special target is set up to the include file name. The commands for the target .INCLUDE_FAILED are called for both, the include and the -include directive. If the commands for the .INCLUDE_FAILED target cannot create a file that is going to be included, smake will fail in case that the include directive was used.

.INIT:
    If this target is present, the target and its dependencies are built before any other target is made.

.KEEP_STATE:
    Reserved by SunPRO make. Don't use this target to avoid problems with the SCHILY (Sing) makefile system.

.KEEP_STATE_FILE:
    Reserved by SunPRO make. Don't use this target to avoid problems with the SCHILY (Sing) makefile system.

.MAKE_VERSION:
    Reserved for future use. Future versions of smake may implement this special target in a way similar to SunPRO make.

    A special target of the form:

        .MAKE_VERSION: smake-number

    forces to check the version of smake. If the version of smake differs from the version in the dependency list, smake issues a warning message. The actual version of smake is smake-1.0

.NO_PARALLEL:
    Reserved for future use.

.NO_WARN:
    If this special target is present and has a dependency list, special warnings may be disabled depending on the names used in the pseudo dependency list.

    If .NO_WARN: does not have any dependencies, the list of warning exceptions is cleared.

    The following pseudo dependencies are implemented:

    :=  Suppress warnings about nonportable ':=' macro assignments.

    $$* Suppress warnings for using the dynamic macro '$*' in explicit rules.

    $$< Suppress warnings for using the dynamic macro '$<' in explicit rules.

.OBJDIR:
    If this special target is present, smake assumes that all files that have been created by a rule should be placed in a special directory called the object directory. The object directory is the only member of the dependency list of the .OBJDIR target. Smake moves the targets automatically into that directory. Automatic macros like $^, $?, $r1 are automatically modified in a way that allows transparent use of the object directory. If .OBJDIR: is not specified, it is assumed to be the current directory '.'.

.OBJSEARCH:
    This target may hold one of three predefined values: src, obj and all. It defines where objects (targets of a rule) are searched for. The default for .OBJSEARCH: is to look for targets in both (source and object) directories or directory lists. See also .SEARCHLIST for a description of the src and obj directories.

.PARALLEL:
    Reserved for future use.

.POSIX:
    If this special target is found, POSIX mode is enabled.

    With this option the verbose command lines written to the stdout stream are prefixed by a TAB character instead of three dots (...). I POSIX mode, smake also calls commands via /bin/sh -c 'cmd' instead of /bin/sh -ce 'cmd'. This causes smake not to stop at failing sub commands in complex commands. If the .POSIX: special target is used, it is highly recommended to also specify MAKE_SHELL_FLAG=-ce to make sure that the make process still stops at failed commands.

.PRECIOUS:
    This macro holds a list of targets that should not be removed while they are built if smake receives a signal. If the list is empty, this applies to all targets.

.PHONY:
    This macro holds a list of targets that should not be checked against existing files. A target that is marked .PHONY will always considered to be out of date. If smake receives a signal, targets marked as .PHONY are not removed. If smake is called with the -t (touch) option, the targets marked as .PHONY are not touched.

.SCCS_GET:
    Reserved for future use.

.SCCS_GET_POSIX:
    Reserved for future use.

.SEARCHLIST:
    .SEARCHLIST is a list of alternate source and object directories where smake should look for targets. This macro may be used as an extended replacement of the VPATH= macro of other make programs. The macro .SEARCHLIST holds a list of srcdir / objdir pairs. The complete internal list is build from '.' .OBJDIR and the content of .SEARCHLIST.

.SILENT:
    Run silently. When this special target is present and has no dependencies, smake will not echo commands before executing them. Specifying .SILENT: without dependencies is equivalent to using the -s option. If .SILENT: has dependencies and the current target is in the list of dependencies of .SILENT: the related commands are not echoed before they are executed.

.SPACE_IN_NAMES:
    If this target is present and has a dependency list, escaped spaces may occur in object and dependency names. If .SPACE_IN_NAMES: is not followed by any dependency, the previous dependencies are cleared and make file parsing is done again in a POSIX compliant way. The following code fragment allows to use non standard space handling for one target only:

    .SPACE_IN_NAMES: true

    target\ with\ spaces: dependency\ with\ spaces
    command list

    .SPACE_IN_NAMES:

.SSUFFIX_RULES:
    If this special macro is present with no dependencies, all current Simple Suffix Rules are cleared.

.SUFFIXES:
    Dependencies of .SUFFIXES are appended to the list of known suffixes and are used in conjunction with the suffix rules (see Suffix Rules). If .SUFFIXES does not have any dependencies, the list of known suffixes is cleared. If the list of .SUFFIXES was cleared, no implicit suffix rule search is done.

.SYM_LINK_TO:
    Reserved for future use.

.WAIT:
    Reserved for future use.

Special Macros

MAKE
    This macro contains a path name that is sufficient to recursively call the same make program again (either that last path component or the full path name of the make program). Note that this may differ from the name that was used on the command line if the name that was used on the command line would not allow to call the same make program from a different directory using this name. For this reason $(MAKE) may not be used to check for a specific make program. Use $(MAKE_NAME) instead. If a command line contains this macro, this command line is executed even if there is no plus sign ('+').

MAKEFLAGS
    This macro contains the command line flags and the command line macros smake is called with. The MAKEFLAGS macro is exported into the environment to allow automatic propagation of make flags and command line macros to sub make programs. The content of this macro is POSIX compliant.

    If there were no command line flags or command line macros, the MAKEFLAGS macro is empty.

    If there were only command line flags, the MAKEFLAGS macro contains a concatenation of the single char versions of the flags. A hyphen is the first char, so MAKEFLAGS would be suitable as a command line flag in this case. A typical content may look this way:
    -id.

    If there were only command line macros, the MAKEFLAGS macro contains a concatenation of the macro specifications. The different macro specifications are separated by a space. Any occurrence of a space or a back slash inside a macro specification is escaped by a back slash. A typical content may look this way:
    CC=gcc COPTX=-DTEST\ -DDEBUG.

    If both command line flags and command line macros are used, the flag part is made as if there were only flags and the macro part is made as if there were only macros. The separator between the flag part and the macro part is a space, two hyphens and a space. A typical content may look this way:
    -id -- CC=gcc COPTX=-DTEST\ -DDEBUG.

    As the MAKEFLAGS notation of the command line macros uses a special escape notation to allow to propagate any possible command line macro, it is not possible to call:
    make $(MAKEFLAGS) from a make file.

MAKE_MACS
    This macro contains the complete set of command line macros and the macros read from the MAKEFLAGS environment. The content is the same as the last part of the MAKEFLAGS macro which holds the macro part. The MAKE_MACS macro is exported into the environment.

MAKE_FLAGS
    This macro contains the command line flags smake is called with. The content is the same as the content of the MAKEFLAGS macro except that no command line macros are added. The MAKE_FLAGS macro is exported into the environment.

MAKE_ARCH
    This macro is set up by smake as part of the automake features of smake. It contains the processor architecture of the current machine (e.g. mc68020, sparc, pentium).

MAKE_BRAND
    This macro is set up by smake as part of the automake features of smake. It contains the brand of the current machine (e.g. Sun_Microsystems).

MAKE_HOST
    This macro is set up by smake as part of the automake features of smake. It contains the host name of the current machine (e.g. duffy, sherwood, ghost).

MAKE_HOST_OS
    This macro is set up by smake as part of the automake features of smake. It contains the host OS name from uname -Hs of the current machine in case that there is a layered OS like Cygwin (e.g. windows).

MAKE_HOST_OSREL
    This macro is set up by smake as part of the automake features of smake. It contains the host OS release from uname -Hr of the current machine in case that there is a layered OS like Cygwin (e.g. 5.1).

MAKE_HOST_OSVERSION
    This macro is set up by smake as part of the automake features of smake. It contains the host OS version from uname -Hv of the current machine in case that there is a layered OS like Cygwin (e.g. sp2).

MAKE_MACH
    This macro is set up by smake as part of the automake features of smake. It contains the kernel architecture of the current machine (e.g. sun3, sun4c, sun4m, sun4u).

MAKE_MODEL
    This macro is set up by smake as part of the automake features of smake. It contains the model name of the current machine (e.g. SUNW,SPARCstation-20).

MAKE_M_ARCH
    This macro is set up by smake as part of the automake features of smake. It contains the machine architecture of the current machine (e.g. sun3, sun4).

MAKE_NAME
    This macro is set up by smake as part of the automake features of smake. It contains the official name of the make program - in our case smake.

MAKE_OS
    This macro is set up by smake as part of the automake features of smake. It contains the operating system name of the current machine (e.g. sunos, linux, dgux).

MAKE_OSDEFS
    This macro is set up by smake as part of the automake features of smake. It contains operating system specific defines for the compiler (e.g. -D__SVR4).

MAKE_OSREL
    This macro is set up by smake as part of the automake features of smake. It contains the operating system release name of the current machine (e.g. 5.5, 4.1.1).

MAKE_OSVERSION
    This macro is set up by smake as part of the automake features of smake. It contains the operating system version of the current machine (e.g. generic).

MAKE_SERIAL
    This macro is set up by smake as part of the automake features of smake. It contains the serial number of the current machine (e.g. 1920098175).

MAKE_SHELL_FLAG
    This macro contains the shell flags used when calling commands from smake. The default value is -ce, When smake in in POSIX mode, the default value is -c. The MAKE_SHELL_FLAG macro allows to overwrite the default behavior.

MAKE_SHELL_IFLAG
    This macro contains the shell flags used when calling commands from smake -i. The default value is -c. The MAKE_SHELL_IFLAG macro allows to overwrite the default behavior.

MAKE_VERSION
    This macro contains the smake version number string.

NUMBER_SIGN
    This macro is predefined to contain the number sign ('#') that is used as the make comment start character and for this reason cannot be appear in non comment parts of regular makefiles.

SHELL
    The SHELL macro is neither imported nor exported from/to the environment. If it is set from within a makefile or from the commandline, the value is used as the name of an alternate shell to execute commands. Makefiles that set SHELL= should be used very carefully as not all platforms support all shells.

VPATH
    This macro implements some object search functionality as found in other UNIX make programs. In smake this functionality is implemented using the .SEARCHLIST: special target, see chapter Search Rules For Files for more information.

Dynamic Macros

There are several internal macros that are updated dynamically. Except $O, they cannot be overwritten. Using them in explicit rules makes the makefile more consistent as the file names do not have to be typed in a second time. Using them in implicit rules is the only way to make implicit rules work as the actual file name cannot be coded into an implicit rule.

If smake uses file name searching, the dynamic macros $<, $0, $n, $r1, $^, and $? are updated to reflect the actual path of the source or object directory.

The dynamic macros are:

$O  expands to the value of .OBJDIR. If .OBJDIR is not defined, $O expands to '.'. If $O has been overwritten, it may no longer be used as a reliable alias for .OBJDIR.

$@  expands to the path name of the current target. It is expanded for both explicit and implicit rules.

$*  expands to the path base name of the current target (the name of the current target with the suffix stripped off). It is expanded for both explicit and implicit rules. POSIX requires that this macro is expanded at least for implicit rules.

$<  expands to the path name of implicit source made in this step. It is expanded for implicit rules only. The existence of this macro is required by POSIX.

$0  expands to the path name of implicit source made in this step. It is expanded for implicit rules only. This macro is available with smake only. It is made available to make the behavior more orthogonal.

$1 $2 $3 ...
    expands to the path name of the nth file in the dependency list. It is expanded for explicit rules only.

$rn expands to the path names of all files in the dependency list starting with the nth. It is valid to specify $r0. It is expanded for both explicit and implicit rules. The 0th entry is available only with implicit rules, the other entries ae available only with explicit rules.

$^  expands to the path names of all files in the dependency list. It is identical to $r1. It is expanded for both explicit rules only.

$?  expands to the path names of all files outdated dependencies for this target. It is expanded for explicit rules only. POSIX requires that this macro is expanded for both explicit and implicit rules.

The following example shows how dynamic macros may be used together with file searching rules:

	foo : main.o lex.o parse.o
		$(CC) -o $@ $^

may expand to:

cc -o foo OBJ/main.o parser/OBJ/lex.o parser/OBJ/parse.o

Implicit Rules

If there is no explicit target rule for a specific target, smake tries to find a matching implicit rule. There are three different types of implicit rules. Pattern Matching Rules are searched first. If no matching pattern matching rule could be found, the Suffix Rules are checked and if there was no matching suffix rule, the Simple Suffix Rules are checked.

Commands defined for implicit rules of any type typically make use of the dynamic macros $@, $* and $< as placeholders for target and dependency file names.

  Pattern Matching Rules

Pattern matching rules have been introduced by SunPRO make with SunOS-3.2 in 1986. They are now also implemented in smake. Pattern matching rules are searched in the same order as they appear in the makefile.

A pattern matching rule looks this way:

    tp%ts: dp%ds
    <tab> command
    ...

In this rule, tp is the target prefix, ts is the target suffix, dp is the dependency prefix and ds is the dependency suffix. Any of the parts may be a null string. The % part of the strings is the base name that matches zero or more characters in the target name. Whenever smake encounters a match with a target pattern of a pattern matching rule, it uses the matching base name to construct dependency names. If the target is out of date relative to the dependency, smake uses the commands from the pattern matching rule to build or rebuild the target.

A rule in the form:

    tp%ts:
    <tab> command
    ...

is permitted.

  Suffix Rules

Suffix rules are the POSIX way of spefifying implicit dependencies. Suffix rules are searched when no pattern matching rule applies. If the special target .SUFFIXES: was cleared or is empty, smake does not check suffix rules. If .SUFFIXES: defines a list of suffixes, the current target file name is checked against this list. If there is a match, the list of suffix rules is checked against the target suffix and a dependency suffix that is also in the .SUFFIXES: list. The search order is derived from the order of suffixes in the suffix list while matching dependency suffixes. A suffix does not need to begin with a '.' to be recognized.

A Double Suffix rule looks this way:

    DsTs:
    <tab> dependency_command
    ...

Ds is the dependency suffix and Ts is the target suffix. They are used when both target file name and dependency file name have a suffix. Double Suffix rules are searched before Single Suffix rules are checked.

A Single Suffix rule looks this way:

    Ds:
    <tab> dependency_command
    ...

Ds is the dependency suffix. Single Suffix rules are used when the target file name does not have a suffix.

  Simple Suffix Rules

Simple suffix rules have the lowest preference when looking for implicit rules. Simple suffix rules are specific to smake.

A simple suffix rule looks this way:

    target_suffix : dependency_1_suffix ...
    <tab> dependency_1_command
    ...

The first line may not start with a TAB character. It starts with the target suffix or "" if no target suffix exists. The target suffix is followed by the target separator (':') and one or more dependency suffixes which are also written as "" if no dependency suffix exists. The first line is followed by exactly the same number of Bourne shell command lines (each starting with a TAB) as there were dependency suffix specifications in the right side of the first line. Each of the Bourne shell command lines correspond to one of the dependency suffixes in the same order.

When smake looks for a possible source for a target with a specific suffix, the dependency suffixes are tried out in the order they appear in the first line of the suffix rule. If a source is found, the corresponding command line is executed.

There may only one simple suffix rule per target suffix. All suffixes except the empty suffix ("") must start with a dot ('.').

The following example shows how a simple suffix rule for creating a zero suffix executable from a .o file may look:

"": .o
$(CC) -o $@ $<

A simple suffix rule that describes how to create a .o file from the possible .c and .s sources may look this way:

.o: .c .s
$(CC) -c $<
$(AS) -o $*.o $<

If smake is going to update foo.c using simple suffix rules, it will first look for a file foo.c and then for a file foo.s. If the file foo.c can be found the first command line ($(CC) -c $<) is executed, if the file foo.s can be found the second command line ($(AS) -o $*.o $<) is executed. Which command is executed depends on which source file exists.

DEFAULT IMPLICIT RULES

Changing the implicit rules allows to change the default behavior of smake.

  Default Simple Suffix Rules

The current default implicit rules are using the simple suffix rule notation are compiled into smake:

FC=f77
RC=f77
PC=pc
AS=as
CC=cc
LEX=lex
YACCR=	yacc -r
YACC=yacc
ROFF=nroff
RFLAGS=-ms
.o: 	.c .s .l
 	$(CC) -c $(CFLAGS) $0
 	$(AS) -o $*.o $0
 	$(LEX) $(LFLAGS) $0;$(CC) -c $(CFLAGS) lex.yy.c;rm lex.yy.c;mv lex.yy.o $@
.c: .y
	$(YACC) $(YFLAGS) $0;mv y.tab.c $@
"":  .o .sc
	$(CC) -o $* $0
	$(ROFF) $(RFLAGS) $0 > $@

If smake reads a file defaults.smk with default implicit rules, the compiled in rules are disabled.

ENVIRONMENT VARIABLES
On startup, smake reads all environment variables (except the SHELL environment) into make macros. The following environment variables affect the behavior of smake.

FORCE_SHELL
    If the FORCE_SHELL environment is present, smake behaves as if the special target .FORCE_SHELL: appeared in a makefile.

LANG
    Sets up a default value for internationalization variables that are unset or NULL:

LC_ALL
    If set, this overrides any other internationalization variables.

LC_CTYPE
    Determine the the interpretation of byte sequences.

LC_MESSAGES
    Determine the diagnostic messages.

MAKE_LEVEL
    This variable is managed by smake to track nested smake calls. It is initialized with 1 and exported. Nested calls to smake increment the level.

MAKEFLAGS
    This variable is set up by smake in order to forward command line options to nested calls to smake. In order to do this, smake sets the content of the MAKEFLAGS variable to contain a list of single character option letters. The option -f is not forwarded via the MAKEFLAGS environment. If command line macro definitions in the form name=value have been specified, the list of option letters is followed by the string " -- " and by a list of macro definitions.

    If any of the name=value command line macro definitions contains a space (' ') or a backslash ('\'), these characters are escaped by a single backslash.

    As required by POSIX, smake accepts all possible variants of formatting the content of the MAKEFLAGS environment.

    See section Special Macros for more information on the MAKEFLAGS environment.

PATH
    The PATH environment variable is used by smake when calling commands. When PATH is modified, this may cause that specific commands cannot be found or that a different implementation with different behavior is found instead.

PROJECTDIR
    This enviroment variable controls the way SCCS history files are searched for. See sccs(1) for more information.

ASYNCHRONOUS EVENTS

If not already ignored by the shell, smake catches SIGHUP, SIGINT, SIGQUIT and SIGTERM and removes the current target unless the current target is a directory, the current target is a prerequisite of the special target .PRECIOUS or the special target .PHONY or one of the options: -t, -q, -p or -n have been specified.

As bash(1) is known to handle signals in a non POSIX compliant way because bash sets up different process groups for non-interactive commands, smake actively propagates the signals named above in case that the autoconfiguration identified /bin/sh to be bash based.

EXIT STATUS

When the -q option is specified, smake exits with one of the following values:

0   Successful completion.

1   The target was not up-to-date.

-1 (255)
    A command line usage error or makefile parsing error occurred.

>0  An error occurred.

When the -q option is not specified, smake exits with one of the following values:

0   Successful completion.

-1 (255)
    A command line usage error or makefile parsing error occurred.

>0  An error occurred.

FILES

SMakefile

Makefile

makefile
    Smake first looks for SMakefile then for Makefile and then for makefile in the current directory to find a list of rules to be used to resolve the targets.

defaults.smk
    If smake finds this file in the current directory, then the implicit rules are read in from this file.

/opt/schily/lib/defaults.smk
    If the file defaults.smk could not be found, then smake tries to read the implicit rules from this file. If this file cannot be found too, then smake uses the rules compiled into smake.

SEE ALSO
sh(1), sccs(1), sysctl(2), sysinfo(2), uname(2), makefiles(4), makerules(4)

NOTES

If a platform uses a shell that does not handle signals correctly and smake does not implement the work around that was mentioned above in the section ASYNCHRONOUS EVENTS, sub makes may continue to run even though the top level make was killed by a signal.

In order to be able to abort complex make structures after a failed command was encountered, the shell needs to behave correctly with the -e option. Bash version 3.x in general and the Korn Shell variant that comes with HP-UX are known to handle the -e option in a non-POSIX compliant way. If the autoconfiguration tests detect a non-compliant /bin/sh and there is a working Bourne Shell available under /bin/bosh or /opt/schily/bin/bosh, smake will use this bosh as the default shell. See the schily source consolidation at: https://sourceforge.net/projects/schilytools/files/

The old schily (SING) makefile system (until late 1999) did only define simple suffix rules. The current version of smake added support for pattern matching rules and POSIX suffix rules. These rules are considered to be rated with higher preference than simple suffix rules. If build in suffix rules can be found, current smake versions will not work correctly with old makefile systems. To use current smake versions with old makefile systems, call smake with the -r flag to disable build in POSIX suffix rules. Newer makefile system version include pattern matching rules that will be searched before the POSIX suffix rules.

A new shell is run for each command line. If you want to run more complicated shell scripts, you need to escape the end of line with a backslash to keep all commands on one virtual shell command line.

Smake tries to be as POSIX compliant as possible.

POSIX does not cover everything that is needed to write portable makefiles suitable to compile large portable projects. Even simple things like macro+=value are not covered by POSIX. Note that adding something to a macro definition is supported by all known make implementations since ~ 1980. In addition, it is most unlikely that different make implementations although POSIX compliant, are compatible enough to maintain large projects. For these reasons, it seems to be better to have a portable make implementation like smake.

BUGS

SCCS retrieval is not yet implemented.

A command line that contains the macro $(MAKE) is always executed, even when in POSIX mode. This is an itended conflict with the POSIX standard since POSIX.1-2008.

Built in library handling is not yet implemented.

There are currently no other known bugs. As smake since spring 1993 is used as the reference make program for the SCHILY (Sing) makefile system, smake is the best choice when compiling projects that are using the SCHILY (Sing) makefile system.

AUTHOR
Joerg Schilling
Seestr. 110
D-13353 Berlin
Germany

Mail bugs and suggestions to:

joerg.schilling@fokus.fraunhofer.de