METALINT(1)

NAME
metalint - a metaconfig unit consistency checker

SYNOPSIS
metalint [ -hklsV ] [ -L dir ]

DESCRIPTION
Metalint parses the units and performs some extensive consistency checks, to make sure the whole set is sound. Due to the relatively huge amount of units available, it is becoming very difficult to maintain the units manually, and an automated process can be of real help, although not perfect.

Metalint operates from within your top level package directory and is used to make sure your own private units are correctly relying on the publicly available units. If you intensively develop new units, you should run metalint on them before making them publicly available.

OPTIONS
Metalint recognizes the following set of options:

-h  Print a short usage description and exit.

-k  Keep temporary .MT directory.

-l  (not implemented yet) By default, metalint only reports problems related to your own private units. This switch directs metalint to also report problems in publicly available units.

-s  Silent mode.

-L dir
    Override default library location. Normally only useful for metaconfig maintainers to locally check the units being developped instead of the publicly available ones. The dir specified is the one containing the units U directory.

-V  Print version number and exit.

DIAGNOSTICS
The following diagnostics may be emitted by metalint:

"(?MAKE) ignoring duplicate dependency listing line."
    More than one ?MAKE: line bearing dependencies was found in the unit. There may be only one such line, although multiple ?MAKE action lines may occur.

"(?MAKE) special unit 'Xxx' should not be listed as made."
    A special unit symbol (first letter capitalized) may only be listed as made in the special unit itself. To suppress this warning in legitimate cases, add a '+' in front of the offending symbol (note that for non-special units, the '+' in this position indicates an internal symbol which should not appear in the config.sh file).

"(?MAKE) '+xxx' is listed x times."
    A conditional dependency is listed more than once. This is harmless though.

"(?MAKE) 'xxx' is listed x times."
    A normal depdendency is listed more than once. Again, an harmless error.

"(?MAKE) 'xxx' listed as both conditional and full dependency."
    Symbol is listed as a normal dependency and as a conditional one. Metaconfig will consider this as being a full dependency, but that may not be what you initially wanted...

"(?Y) unknown layout directive 'xxx'."
    Layout directives may only be one of top, default or bottom, but case does not matter. An unknown directive is just ignored and handled as if default had been specified.

"(?S) duplicate description for variable '$xxx'."
    Shell symbol is described more than once, and that will produce two entries in the Glossary.

"(?S) variable '$xxx' is not listed on ?MAKE: line."
    The unit describes a shell symbol entry which cannot be used externally since not listed as a dependency.

"(?S) syntax error in ?S: construct."
    Self explainatory.

"(?C) duplicate description for symbol 'XXX'."
    C symbol is described more than once, and that will produce two entries for it in the Glossary.

"(?C) syntax error in ?C: construct."
    Self explainatory.

"(?H) symbol 'XXX' was already defined."
    Apparently, two ?H: lines are defining the same C symbol.

"(?H) variable '$xxx' not even listed on ?MAKE: line."
    A variable is used, but not listed on the dependency line.

"(?M) syntax error in ?M: construct."
    Self explainatory.

"(?M) symbol 'xxx' already listed on a ?M: line in 'yyy'."
    A magic definition for symbol xxx is attempted, but another one was already provided in unit yyy.

"(?V) visible declaration in non-special unit ignored."
    Visible declarations (?V: lines) may only appear in special units. Otherwise, they are meaningless.

"(?V) wanted variable '$xxx' made visible."
    A wanted variable (described as a dependency on the ?MAKE: line) cannot be made visible since that does not make any sense: the unit cannot depend on it and then advertise it as being locally defined.

"(?V) defined variable '$xxx' made visible."
    A defined variable (listed as made on the ?MAKE: line) cannot be made visible, since it could as well be directly wanted in another unit.

"(?V) variable '$xxx' already made visible by unit yyy."
    Inconsistent declaration: two units are making one single symbol visible...

"(?V) variable '$xxx' already read-write visible in yyy."
    The variable was already made visible as read-write by another unit.

"(?V) variable '$xxx' already read-only visible in yyy."
    The variable was already made visible as read-only by another unit.

"(?W) variable '$xxx' already wanted."
    Variable is already wanted, there is no need to explicitely ask for it here.

"(?W) variable '$xxx' also locally defined."
    A wanted variable would conflict with a locally defined variable and could result in getting a garbage value.

"(?W) variable '$xxx' already listed on a ?W: line in 'yyy'."
    The variable in the shell symbol section of a ?W: line can only appear in one unit.

"(?F) produced file 'xxx' mutiply declared."
    The file is listed more than once on the ?F: line, under the same name. This does not appear when declaring both a private UU file and a public file with the same name, for instance.

"(?F) UU file  in non-special unit ignored."
    Private UU files (i.e. files like the myread script created for later perusal by Configure) may only be created in special units. Exceptions allowed if the ?F: line is preceded by a proper ?LINT: hint.

"(?T) temporary symbol '$xxx' multiply declared."
    Self explainatory.

"control sequence '?XXX:' ignored within body."
    Attempt to use a control line other than ?X: or ?LINT: in the unit body, which should be only shell code

"variable '$xxx' is changed."
    A variable listed as wanted in the dependency line is changed. Such a variable should be read-only for the unit. Use the change lint hint to suppress this message in pathological cases.

"no ?MAKE: line describing dependencies."
    Every unit should have a dependency line, or it will be silently ignored by metaconfig. This message is suppressed by a ?LINT: empty hint.

"not ending with a blank line."
    Since all units are gathered together to form one big script, it is recommended (hence enforced by metalint) that every unit file end with an empty line.

"last line not ending with a new-line character."
    This is merely intended to users whose editor does not always append a new-line at the end of text files. Should not happen when you use vi.

"symbol '$xxx' was not described."
    The shell symbol defined by this unit was not documented. Use the describe lint hint to suppress this message.

"C symbol 'XXX' was not described."
    The C symbol defined by this unit was not documented. Use the known lint hint to suppress this message.

"C symbol 'XXX' was not defined by any ?H: line."
    A C symbol was advertised by never defined, hence it cannot appear in the config.h file and is therefore useless...

"variable '$xxx' should have been set."
    A variable listed on the make line as made by the unit was not set by the shell code body. Use the set lint hint to suppress this message in pathological cases.

"unused dependency variable '$xxx'."
    Apparently no usage is made from a shell variable. Use the change or use lint hints (depending on the situation) to suppress this message.

"unused conditional variable '$xxx'.
    Apparently no usage is made from this conditional dependency. The change or use lint hints can be used to suppress this message.

"unused temporary variable '$xxx'."
    A variable declared as temporary in a ?T: line is not used. The use lint hint will fool metalint into thinking it's indeed used.

"unknown control sequence '?XXX:'."
    Attempt to use an unknown control sequence.

"unknown LINT request 'bsd' ignored."
    An unknown ?LINT: tag was used. All such tags must be spelled out in lowercase.

"symbol '$xxx' has no default value."
    A symbol used as a conditional dependency in some unit has no default value set by a ?D: line.

"stale ?MAKE: dependency 'xxx'."
    Unit lists a symbol as a dependency, but that symbol is otherwise unknown, i.e. never appears as made by any other unit.

"symbol '$xxx' missing from ?MAKE."
    A symbol used or defined was not listed as a dependency in the ?MAKE: line.

"missing xxx from ?MAKE for visible '$yyy'."
    A symbol defined as visible by a special unit is used, but that special unit is not part of the dependency line.

"stale ?M: dependency 'xxx'."
    Magic line lists a C symbol as a dependency but that symbol is not known by any unit.

"unknown symbol '$xxx'."
    I have no idea about what this symbol is. If the variable is externally define, this warning can be suppresed via a proper ?LINT: extern.

"read-only symbol '$xxx' is set."
    A symbol that should be read-only is set by the unit's shell code body.

"obsolete symbol 'xxx' is used."
    An obsolete symbol is used in the unit's shell code.

"undeclared symbol '$xxx' is set."
    The unit tries to set a shell variable which has not been otherwise declared as made or as a temporary variable, or whatever.

"meaningful shell character '>' in comment line."
    A shell charcter like '>' or ';' was found on a : comment line, which is parsed by the shell, although not executed. Therefore, those symbols are dangerous and can cause weird behaviour, and should be avoided if possible.

"unmatched single quote in comment line."
    The : comment line is parsed by the shell, so any unmatched quote will result in having a chunk of the produced Configure script ignored at interpretation time, causing trouble at best. A similar message will be issued for unmatched double quotes.

"C symbol 'xxx' is defined in the following units:"
    The C symbol is defined in more that one unit. Offending units are listed.

"Shell symbol 'xxx' is defined in the following units:"
    A shell symbol is defined in more than one unit. Offending units folllow.

"Shell symbol 'xxx' is altogether:"
    A shell symbol is defined by some units, obsoleted by others and used as a temporary.

"Shell symbol 'xxx' is both defined and obsoleted:"
    Self explainatory.

"Shell symbol 'xxx' is both defined and used as temporary:"
    Self explainatory.

"Shell symbol 'xxx' obsoleted also used as temporary:"
    Self explainatory.

"definition of '$xxx' not closed by '?S:.'."
    Self explainatory.

"definition of 'XXX' not closed by '?C:.'."
    Self explainatory.

"magic definition of 'xxx' not closed by '?M:.'."
    Self explainatory.

"variable '$xxx' is defined externally."
    A variable defined externally (i.e. in another unit) is used, without proper dependency information. Use the extern lint hint to suppress this message.

"file 'xxx' was not created."
    A file listed as a private UU file is not created by the special unit. Creation is detected by seing an explicit shell redirection to the file, not by an implicit creation (such as a C compilation would for instance). All special units should create only shell scripts explicitely anyway so this message cannot be suppressed via a lint hint.

"local file 'xxx' may override the one set by 'unit.U'."
    You are attempting to create a local file, but the special unit creates one bearing the exact same name and should it be loaded before within Configure, you would override that file. Change the name of your local file.

"unused temporary file 'xxx'.
    The file was declared on the ?F: line but does not appear to be used anywhere.

"mis-used temporary file 'xxx'.
    A local temporary file has been declared on the ?F: line and is used in a way that may not be the proper one. Indeed, all such local files should be called with an explicit relative path, to avoid PATH lookups which could get you another file.

"you might not always get file 'xxx' from 'unit.U'."
    You seem to be calling the specified file, but not by using an explicit relative pathname. Relying on the PATH to find this file is not safe. To fix this problem, call your file using somthing like ./xxx.

"missing Unit from ?MAKE for private file 'xxx'."
    You are using a private UU file without listing the special unit that produces it in your dependency line. Add the unit to your dependency list.

"unknown private file 'xxx'."
    The file does not appear on any ?F: line; however it should.

"File 'xxx' is defined in the following units:"
    The listed units cannot seem to agree on who is defining the file.

"Cycle found for:"
    There is a dependency cycle found for the symbols listed. Only the symbols involved in the cycle are listed.

"Cycle involves:"
    An exerpt of the dependencies where the cycle was found is listed. This may involve far more symbols than the previous message, because metalint actually rescans the rules to emphasize the cycle and stops whenever it has found one, i.e. it does not try to minimize it (the cycle is found using another algorithm, which unfortunately cannot spit it out but only say for sure there is one).

REFERENCE
Metalint uses the following control lines, which are otherwise ignored by metaconfig:

?V:read-only symbols:read-write symbols
    This line should be used only in special units. It lists all the shell variable defined by the unit which should not be used directly as dependencies by other units: they must include this special unit in their dependency list if they make use of any of the symbols described here. Those can be viewed as exported symbols which you inherit from when depending from the unit. Symbols may be exported read-only or read-write.

?F:files created
    This line serves two purposes: it is a metalint hint, and also a placeholder for future jmake use. It must list three kind of files: the temporary one which are created for a test, the private UU ones created in the UU directory for later perusal, and the public ones left in the root directory of the package. Temporary files must be listed with a preceding '!' character (meaning "no! they're not re-used later!"), private UU files should be preceded by a './' (meaning: to use them, say ./file, not just file), and public ones should be named as-is.

?T:shell temporaries
    This line should list all the shell variables used as temporaries within the unit's body. This line should be kept accurate, and prevents you from writing a unit defining a symbol which would be used as a scratch variable in another unit...

?LINT:keyword symbol_list
    Specifies a lint hint. The following keywords are available:

    change
        shell variable ok to be changed
    create
        persistent file ok to be created by non-special unit
    define
        shell variables listed are defined in this unit
    describe
        listed shell variables are described by ?S:
    extern
        variable known to be externally defined
    empty
        unit file is empty and kept only as a placeholder.
    known
        listed C variables are described
    set listed variables are set
    use variables listed are used by this unit

AUTHORS
Harlan Stenn <harlan@mumps.pfcs.com> wrote the first version, based on Larry Wall's metaconfig from dist 2.0.
Raphael Manfredi <ram@hptnos02.grenoble.hp.com> rewrote it from scratch for 3.0 with a few enhancements.

FILES

LIB/dist/mcon/U/*.U
    Public unit files
U/*.U
    Private unit files

    where LIB is /u/vieraat/vieraat/jhi/Perl/lib/dist.

BUGS
Maybe.

SEE ALSO
metaconfig(1), metaxref(1)