make.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)make.1	8.1	9/11/90
.TH make 1
.SH Name
make, s5make \- maintain, update, and regenerate groups of programs
.SH Syntax
.B make
[
.B \-f
.I makefile
]
[
.I options
]
[
.I names
] 
.PP
.B s5make
[
.B \-f
.I makefile
]
[
.I options
]
[
.I names
] 
.SH Description
.NXR "make keyword"
.NXR "make command"
.NXR "program" "updating"
.NXR "file" "updating"
.PP
This is the SYSTEM V version of the
.PN make
command with some Berkeley compatibility added.
.SH Options
.NXR "make command (System V)" "options"
.IP \-b 15
Compatibility mode for old makefiles.
.IP \-d
Debug mode.
Displays detailed information on files
and times examined.
.IP \-e
Causes environment variables to override assignments within makefiles.
.IP "\-f \fImakefile\fR"
Uses the specified description file name. 
A file name of
.B \-
denotes the standard input.
The contents of the file specified as
.I makefile
override the built-in rules.
.IP \-i
Ignores error codes returned by invoked commands.
This
mode is entered if the special target name .IGNORE
appears in the description file.
.IP \-k
Stops work on the current
entry, but continues on other branches
that do not depend on that entry.
.IP \-m
Displays a memory map showing text, data, and the stack.
Does not operate on systems without the 
.PN getu 
system call.
.IP \-n
No execute mode.
Displays commands, but does not execute
them.
Even lines beginning with an at sign (@) are printed.
.IP \-p
Displays the complete set of macro definitions and target descriptions.
.IP \-q
Question mode.
Returns a zero or nonzero
status code depending on whether the target file is or
is not up to date.
.IP \-r
Does not use the built-in rules.
.IP \-s
Silent mode.
Suppresses the display of command lines before executing.
This mode is also entered if the special target name .SILENT
appears in the description file.
.IP \-S
Abandon work on the current entry if it fails; the opposite of the
.B \-k
option.  If both options are specified, the last one specified
on the command line is used.
.IP \-t
Touches target files (causing them to be up to date)
rather than issuing usual commands.
.SH Special Names
.TP 15
\& .DEFAULT
If a file must be made but there are no explicit commands
or relevant built-in rules, the commands associated
with the name .DEFAULT
are used if it exists.
.TP
\&.PRECIOUS
Dependents of this target are not removed when
quit or interrupt is hit.
.TP
\&.SILENT
Same effect as the 
.B \-s 
option.
.TP
\&.IGNORE
Same effect as the 
.B \-i 
option.
.TP
\&.SUFFIXES
Dependencies of the .SUFFIXES special target are added to the table of
known suffixes.
.SH Discussion
The
.PN make
program executes commands in
.I makefile
to update
one or more target
.I names .
The
.I name
argument is typically a program.
If no
.B \-f
option is present, \fBmakefile\fP, \fBMakefile\fP, \fBs.makefile\fP,
and \fBs.Makefile\fP are
tried in order.
If
.I makefile
is \fB\-\fR, the standard input is taken.
You can specify more than one
.B \-f
.I makefile
argument.
.PP
The
.PN make
program updates a target only if its dependents are
newer than the target.
All prerequisite files of a target are added recursively to
the list of targets.
Missing files are deemed to be out of date.
.PP
The
.I makefile
argument contains a sequence of entries that specify dependencies.
The first line of an entry is a
blank-separated, non-null list of targets, then a
colon (:),
then a (possibly null) list of prerequisite files or dependencies.
Text following a
semicolon (;)
and all following lines
that begin with a tab are shell commands
to be executed to update the target.
The first line that does not begin with a tab or 
number sign (#) begins
a new dependency or macro definition.
Shell commands can
be continued across lines with the backslash followed 
by a new-line (\RET) sequence.
Everything printed by 
.PN make 
(except the initial tab) is passed
directly to the shell.
For example:
.EX
echo a\\
b
.EE
These entries produce the following:
.EX
ab
.EE
This output is exactly the same as what would have been produced
by the shell.
.PP
Number sign (#)
and new-line surround comments.
.PP
The following
.I makefile
says that
.B pgm
depends on two
files
.PN a.o
and
.PN b.o ,
and that they in turn depend on
their corresponding source files
.PN (a.c
and
.PN b.c)
and a common file
.PN incl.h:
.EX
pgm: a.o b.o
   cc a.o b.o \-o pgm
a.o: incl.h a.c
   cc \-c a.c
b.o: incl.h b.c
   cc \-c b.c
.EE
.PP
Command lines are executed one at a time, each by its
own shell.
The first one or two characters in a command can be
the following: \-, @, \-@, or @\-.
If @ is present, printing of the command is suppressed.
If \- is present, 
.PN make
ignores an error.
A line is printed when it is executed unless the
.B \-s
option is present, or the entry
\&.SILENT:
is in
.IR makefile ,
or unless the initial character sequence contains a @.
The
.B \-n
option specifies printing without execution.  However, if the
command line has the string
$(MAKE)
in it,
the line is
always executed (see discussion of the MAKEFLAGS
macro under
.B Environment).
The
.B \-t
(touch) option updates the modified date of a
file without executing any commands.
.PP
Commands returning nonzero status normally terminate
.PN make .
If the
.B \-i
option is present, or the entry \.IGNORE: appears in
.IR makefile ,
or the initial character sequence of the command 
contains \-, the error is ignored.
If the
.B \-k
option is present, work stops on the current
entry, but continues on other branches that do not depend on that entry.
.PP
The
.B \-b
option allows old makefiles (those written for the old version of 
.PN make )
to run without errors.
The difference between the old version
of 
.PN make
and this version is that this version requires all dependency
lines to have a (possibly null or implicit) command associated with them.
The previous version of
.PN make
assumed, if no command was specified explicitly,
that the command was null.
.PP
Interrupt and quit cause the target to be deleted
unless the target is a dependent
of the special name .PRECIOUS.
.SS Environment
The environment is always read by 
.PN make .
All variables are assumed to be macro definitions and processed as such.
The
.B \-e
option causes
the environment to override the macro assignments in a makefile.
.PP
The
.PN make
command operates in three compatibility modes.  The type of mode is
determined by value of the PROG_ENV environment variable and by
the way that
.PN make
is executed.  The PROG_ENV variable has three valid values:
.IP \(bu
BSD
.IP \(bu
POSIX
.IP \(bu
SYSTEM_FIVE 
.PP
In BSD mode,
.PN make
executes with Berkeley compatibility.  This means that 
.PN /bin/sh
is always used as the command interpreter regardless of the value of
SHELL, and the commands are echoed to standard out without a prefixed
<tab>. 
.PP
In POSIX mode,
.PN make
executes with POSIX compatibility, such that the SHELL environment
variable is always ignored, SHELL is always overridden by MAKESHELL, the
shell is always used to execute commands, and commands are echoed to
standard out with a prefixed <tab>. 
.PP
SYSTEM_FIVE mode causes
.PN make
to run with SYSTEM V compatibility such that SHELL is used to execute
commands and commands are echoed to standard out with a prefixed <tab>.
.PP
For all modes, SHELL has a default value of 
.PN /bin/sh.  
When
.PN make
is executed with the command name
.PN s5make ,
it always executes in SYSTEM_FIVE mode and ignores the environment
variable PROG_ENV.
.PP
The MAKEFLAGS environment variable
is processed by 
.PN make 
as containing
any legal input option
(except