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Fix Savannah bugs # 15341, 15534, and 15533.

Browse source 
Rewrite large chunks of the "Commands" section of the manual to better
describe then backslash-newline handling, the SHELL variable, etc.
This commit is contained in:
Paul Smith 2006-02-06 16:21:59 +00:00
parent 7a8549f5dd
commit a4e3523fe4
9 changed files with 479 additions and 223 deletions
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23
ChangeLog
View file

@ -1,3 +1,26 @@
2006-02-06 Paul D. Smith <psmith@gnu.org>
* vpath.c (selective_vpath_search): If the file we find has a
timestamp from -o or -W, use that instead of the real time.
* remake.c (f_mtime): If the mtime is a special token from -o or
-W, don't overwrite it with the real mtime.
Fixes Savannah bug #15341.
2006-02-05 Paul D. Smith <psmith@gnu.org>
* file.c (enter_file): Keep track of the last double_colon entry,
to avoid walking the list every time we want to add a new one.
Fixes Savannah bug #15533.
* filedef.h (struct file): Add a new LAST pointer.
* dir.c (directory_contents_hash_cmp): Don't use subtraction to do
the comparison. For 64-bits systems the result of the subtraction
might not fit into an int. Use comparison instead.
Fixes Savannah bug #15534.
* doc/make.texi: Update the chapter on writing commands to reflect
the changes made in 3.81 for backslash/newline and SHELL handling.
2006-02-01 Paul D. Smith <psmith@gnu.org>
* dir.c (dir_contents_file_exists_p) [WINDOWS32]: Make sure

23
dir.c
View file

@ -289,6 +289,17 @@ directory_contents_hash_2 (const void *key_0)
return hash;
}
/* Sometimes it's OK to use subtraction to get this value:
result = X - Y;
But, if we're not sure of the type of X and Y they may be too large for an
int (on a 64-bit system for example). So, use ?: instead.
See Savannah bug #15534.
NOTE! This macro has side-effects!
*/
#define MAKECMP(_x,_y) ((_x)<(_y)?-1:((_x)==(_y)?0:1))
static int
directory_contents_hash_cmp (const void *xv, const void *yv)
{
@ -300,28 +311,28 @@ directory_contents_hash_cmp (const void *xv, const void *yv)
ISTRING_COMPARE (x->path_key, y->path_key, result);
if (result)
return result;
result = x->ctime - y->ctime;
result = MAKECMP(x->ctime, y->ctime);
if (result)
return result;
#else
# ifdef VMS
result = x->ino[0] - y->ino[0];
result = MAKECMP(x->ino[0], y->ino[0]);
if (result)
return result;
result = x->ino[1] - y->ino[1];
result = MAKECMP(x->ino[1], y->ino[1]);
if (result)
return result;
result = x->ino[2] - y->ino[2];
result = MAKECMP(x->ino[2], y->ino[2]);
if (result)
return result;
# else
result = x->ino - y->ino;
result = MAKECMP(x->ino, y->ino);
if (result)
return result;
# endif
#endif /* WINDOWS32 */
return x->dev - y->dev;
return MAKECMP(x->dev, y->dev);
}
/* Table of directory contents hashed by device and inode number. */

472
doc/make.texi
View file

@ -10,8 +10,8 @@
@set RCSID $Id$
@set EDITION 0.70
@set VERSION 3.81
@set UPDATED 29 Jan 2006
@set UPDATE-MONTH Jan 2006
@set UPDATED 5 Feb 2006
@set UPDATE-MONTH Feb 2006
@c ISBN provided by Lisa M. Opus Goldstein <opus@gnu.org>, 5 May 2004
@set ISBN 1-882114-83-5
@ -39,7 +39,7 @@ This is Edition @value{EDITION}, last updated @value{UPDATED},
of @cite{The GNU Make Manual}, for @code{make}, Version @value{VERSION}.
Copyright 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
1998, 1999, 2000, 2002, 2003, 2004, 2005
1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006
Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
@ -173,8 +173,8 @@ Writing Rules
* Directory Search:: Searching other directories for source files.
* Phony Targets:: Using a target that is not a real file's name.
* Force Targets:: You can use a target without commands
or prerequisites to mark other
targets as phony.
or prerequisites to mark other targets
as phony.
* Empty Targets:: When only the date matters and the
files are empty.
* Special Targets:: Targets with special built-in meanings.
@ -214,6 +214,7 @@ Static Pattern Rules
Writing the Commands in Rules
* Command Syntax:: Command syntax features and pitfalls.
* Echoing:: How to control when commands are echoed.
* Execution:: How commands are executed.
* Parallel:: How commands can be executed in parallel.
@ -301,8 +302,8 @@ Using Implicit Rules
* Implicit Variables:: How to change what predefined rules do.
* Chained Rules:: How to use a chain of implicit rules.
* Pattern Rules:: How to define new implicit rules.
* Last Resort:: How to defining commands for rules
which cannot find any.
* Last Resort:: How to define commands for rules which
cannot find any.
* Suffix Rules:: The old-fashioned style of implicit rule.
* Implicit Rule Search:: The precise algorithm for applying
implicit rules.
@ -331,15 +332,6 @@ Implicit Rule for Archive Member Targets
* Archive Symbols:: How to update archive symbol directories.
Makefile Conventions
* Makefile Basics:: General Conventions for Makefiles
* Utilities in Makefiles:: Utilities in Makefiles
* Command Variables:: Variables for Specifying Commands
* Directory Variables:: Variables for Installation Directories
* Standard Targets:: Standard Targets for Users
* Install Command Categories:: Three categories of commands in the `install'
@end detailmenu
@end menu
@ -1852,8 +1844,8 @@ the makefile (often with a target called @samp{all}).
* Directory Search:: Searching other directories for source files.
* Phony Targets:: Using a target that is not a real file's name.
* Force Targets:: You can use a target without commands
or prerequisites to mark other
targets as phony.
or prerequisites to mark other targets
as phony.
* Empty Targets:: When only the date matters and the
files are empty.
* Special Targets:: Targets with special built-in meanings.
@ -1937,19 +1929,23 @@ target per rule, but occasionally there is a reason to have more
The @var{command} lines start with a tab character. The first command may
appear on the line after the prerequisites, with a tab character, or may
appear on the same line, with a semicolon. Either way, the effect is the
same. @xref{Commands, ,Writing the Commands in Rules}.
same. There are other differences in the syntax of command lines.
@xref{Commands, ,Writing the Commands in Rules}.
@cindex dollar sign (@code{$}), in rules
@cindex @code{$}, in rules
@cindex rule, and @code{$}
Because dollar signs are used to start variable references, if you really
want a dollar sign in a rule you must write two of them, @samp{$$}
(@pxref{Using Variables, ,How to Use Variables}). In prerequisite
lists you must actually write @emph{four} dollar signs (@samp{$$$$}),
due to secondary expansion (@pxref{Secondary Expansion}).
You may split a long line by inserting a backslash
followed by a newline, but this is not required, as @code{make} places no
limit on the length of a line in a makefile.
@cindex rules, and @code{$}
Because dollar signs are used to start @code{make} variable
references, if you really want a dollar sign in a target or
prerequisite you must write two of them, @samp{$$} (@pxref{Using
Variables, ,How to Use Variables}). If you have enabled secondary
expansion (@pxref{Secondary Expansion}) and you want a literal dollar
sign in the prerequisites lise, you must actually write @emph{four}
dollar signs (@samp{$$$$}).
You may split a long line by inserting a backslash followed by a
newline, but this is not required, as @code{make} places no limit on
the length of a line in a makefile.
A rule tells @code{make} two things: when the targets are out of date,
and how to update them when necessary.
@ -3497,28 +3493,17 @@ object file become the default goal.
@cindex rule commands
@cindex writing rule commands
The commands of a rule consist of shell command lines to be executed one
by one. Each command line must start with a tab, except that the first
command line may be attached to the target-and-prerequisites line with a
semicolon in between. Blank lines and lines of just comments may appear
among the command lines; they are ignored. (But beware, an apparently
``blank'' line that begins with a tab is @emph{not} blank! It is an
empty command; @pxref{Empty Commands}.)
The commands of a rule consist of one or more shell command lines to
be executed, one at a time, in the order they appear. Typically, the
result of executing these commands is that the target of the rule is
brought up to date.
Users use many different shell programs, but commands in makefiles are
always interpreted by @file{/bin/sh} unless the makefile specifies
otherwise. @xref{Execution, ,Command Execution}.
@cindex comments, in commands
@cindex commands, comments in
@cindex @code{#} (comments), in commands
The shell that is in use determines whether comments can be written on
command lines, and what syntax they use. When the shell is
@file{/bin/sh}, a @samp{#} starts a comment that extends to the end of
the line. The @samp{#} does not have to be at the beginning of a line.
Text on a line before a @samp{#} is not part of the comment.
@menu
* Command Syntax:: Command syntax features and pitfalls.
* Echoing:: How to control when commands are echoed.
* Execution:: How commands are executed.
* Parallel:: How commands can be executed in parallel.
@ -3529,96 +3514,87 @@ Text on a line before a @samp{#} is not part of the comment.
* Empty Commands:: Defining useful, do-nothing commands.
@end menu
@node Echoing, Execution, Commands, Commands
@section Command Echoing
@cindex echoing of commands
@cindex silent operation
@cindex @code{@@} (in commands)
@cindex commands, echoing
@cindex printing of commands
@node Command Syntax, Echoing, Commands, Commands
@section Command Syntax
@cindex command syntax
@cindex syntax of commands
Normally @code{make} prints each command line before it is executed.
We call this @dfn{echoing} because it gives the appearance that you
are typing the commands yourself.
Makefiles have the unusual property that there are really two distinct
syntaxes in one file. Most of the makefile uses @code{make} syntax
(@pxref{Makefiles, ,Writing Makefiles}). However, commands are meant to be
interpreted by the shell and so they are written using shell syntax.
The @code{make} program does not try to understand shell syntax: it
performs only a very few specific translations on the content of the
command before handing it to the shell.
When a line starts with @samp{@@}, the echoing of that line is suppressed.
The @samp{@@} is discarded before the command is passed to the shell.
Typically you would use this for a command whose only effect is to print
something, such as an @code{echo} command to indicate progress through
the makefile:
Each command line must start with a tab, except that the first command
line may be attached to the target-and-prerequisites line with a
semicolon in between. @emph{Any} line in the makefile that begins
with a tab and appears in a ``rule context'' (that is, after a rule
has been started until another rule or variable definition) will be
considered a command line for that rule. Blank lines and lines of
just comments may appear among the command lines; they are ignored.
@example
@@echo About to make distribution files
@end example
Some consequences of these rules include:
@cindex @code{-n}
@cindex @code{--just-print}
@cindex @code{--dry-run}
@cindex @code{--recon}
When @code{make} is given the flag @samp{-n} or @samp{--just-print}
it only echoes commands, it won't execute them. @xref{Options Summary,
,Summary of Options}. In this case and only this case, even the
commands starting with @samp{@@} are printed. This flag is useful for
finding out which commands @code{make} thinks are necessary without
actually doing them.
@itemize @bullet
@item
A blank line that begins with a tab is not blank: it's an empty
command (@pxref{Empty Commands}).
@cindex @code{-s}
@cindex @code{--silent}
@cindex @code{--quiet}
@findex .SILENT
The @samp{-s} or @samp{--silent}
flag to @code{make} prevents all echoing, as if all commands
started with @samp{@@}. A rule in the makefile for the special target
@code{.SILENT} without prerequisites has the same effect
(@pxref{Special Targets, ,Special Built-in Target Names}).
@code{.SILENT} is essentially obsolete since @samp{@@} is more flexible.@refill
@cindex comments, in commands
@cindex commands, comments in
@cindex @code{#} (comments), in commands
@item
A comment in a command line is not a @code{make} comment; it will be
passed to the shell as-is. Whether the shell treats it as a comment
or not depends on your shell.
@node Execution, Parallel, Echoing, Commands
@section Command Execution
@cindex commands, execution
@cindex execution, of commands
@cindex shell command, execution
@vindex SHELL @r{(command execution)}
@item
A variable definition in a ``rule context'' which is indented by a tab
as the first character on the line, will be considered a command line,
not a @code{make} variable definition, and passed to the shell.
When it is time to execute commands to update a target, they are executed
by making a new subshell for each line. (In practice, @code{make} may
take shortcuts that do not affect the results.)
@item
A conditional expression (@code{ifdef}, @code{ifeq},
etc. @pxref{Conditional Syntax, ,Syntax of Conditionals}) in a ``rule
context'' which is indented by a tab as the first character on the
line, will be considered a command line and be passed to the shell.
@cindex @code{cd} (shell command)
@strong{Please note:} this implies that shell commands such as
@code{cd} that set variables local to each process will not affect the
following command lines.@footnote{On MS-DOS, the value of current
working directory is @strong{global}, so changing it @emph{will}
affect the following command lines on those systems.} If you want to
use @code{cd} to affect the next command, put them on a single line.
Then @code{make} will consider them a single command and pass them
both to a single shell which will execute them in sequence. For
example:
@end itemize
@example
foo : bar/lose
cd $(@@D) && gobble $(@@F) > ../$@@
@end example
@noindent
Here we use the shell AND operator (@code{&&}) so that if the
@code{cd} command fails, the script will fail without trying to invoke
the @code{gobble} command in the wrong directory, which could very
easily cause problems (in this case it would certainly cause
@file{../foo} to be truncated, at least).
@menu
* Splitting Lines:: Breaking long command lines for readability.
* Variables in Commands:: Using @code{make} variables in commands.
@end menu
@node Splitting Lines, Variables in Commands, Command Syntax, Command Syntax
@subsection Splitting Command Lines
@cindex commands, splitting
@cindex splitting commands
@cindex commands, backslash (@code{\}) in
@cindex commands, quoting newlines in
@cindex backslash (@code{\}), in commands
@cindex @code{\} (backslash), in commands
@cindex quoting newline, in commands
@cindex newline, quoting, in commands
A shell command can be split into multiple lines of text by placing a
backslash before each newline. Such a sequence of lines is provided
to the shell as a single command script. The backslash and newline
are preserved in the shell command. If the first character on the
line after a backslash-newline is a tab, the tab will @emph{not} be
included in the shell command. So, this makefile:
One of the few ways in which @code{make} does interpret command lines
is checking for a backslash just before the newline. As in normal
makefile syntax, a single command can be split into multiple lines in
the makefile by placing a backslash before each newline. A sequence
of lines like this is considered a single command, and one instance of
the shell will be invoked to run it.
However, in contrast to how they are treated in other places in a
makefile, backslash-newline pairs are @emph{not} removed from the
command. Both the backslash and the newline characters are preserved
and passed to the shell. How the backslash-newline is interpreted
depends on your shell. If the first character of the next line
after the backslash-newline is a tab, then that tab (and only that
tab) is removed. Whitespace is never added to the command.
For example, this makefile:
@example
@group
@ -3685,9 +3661,220 @@ quotes (@code{'...'}). This is the way the default shell (@file{/bin/sh})
handles backslash/newline pairs. If you specify a different shell in your
makefiles it may treat them differently.
Sometimes you want to split a long line inside of single quotes, but
you don't want the backslash-newline to appear in the quoted content.
This is often the case when passing scripts to languages such as Perl,
where extraneous backslashes inside the script can change its meaning
or even be a syntax error. One simple way of handling this is to
place the quoted string, or even the entire command, into a
@code{make} variable then use the variable in the command. In this
situation the newline quoting rules for makefiles will be used, and
the backslash-newline will be removed. If we rewrite our example
above using this method:
@example
@group
HELLO = 'hello \
world'
all : ; @@echo $(HELLO)
@end group
@end example
@noindent
we will get output like this:
@example
@group
hello world
@end group
@end example
If you like, you can also use target-specific variables
(@pxref{Target-specific, ,Target-specific Variable Values}) to obtain
a tighter correspondence between the variable and the command that
uses it.
@node Variables in Commands, , Splitting Lines, Command Syntax
@subsection Using Variables in Commands
@cindex variable references in commands
@cindex commands, using variables in
The other way in which @code{make} processes commands is by expanding
any variable references in them (@pxref{Reference,Basics of Variable
References}). This occurs after make has finished reading all the
makefiles and the target is determined to be out of date; so, the
commands for targets which are not rebuilt are never expanded.
Variable and function references in commands have identical syntax and
semantics to references elsewhere in the makefile. They also have the
same quoting rules: if you want a dollar sign to appear in your
command, you must double it (@samp{$$}). For shells like the default
shell, that use dollar signs to introduce variables, it's important to
keep clear in your mind whether the variable you want to reference is
a @code{make} variable (use a single dollar sign) or a shell variable
(use two dollar signs). For example:
@example
@group
LIST = one two three
all:
for i in $(LIST); do \
echo $$i; \
done
@end group
@end example
@noindent
results in the following command being passed to the shell:
@example
@group
for i in one two three; do \
echo $i; \
done
@end group
@end example
@noindent
which generates the expected result:
@example
@group
one
two
three
@end group
@end example
@node Echoing, Execution, Command Syntax, Commands
@section Command Echoing
@cindex echoing of commands
@cindex silent operation
@cindex @code{@@} (in commands)
@cindex commands, echoing
@cindex printing of commands
Normally @code{make} prints each command line before it is executed.
We call this @dfn{echoing} because it gives the appearance that you
are typing the commands yourself.
When a line starts with @samp{@@}, the echoing of that line is suppressed.
The @samp{@@} is discarded before the command is passed to the shell.
Typically you would use this for a command whose only effect is to print
something, such as an @code{echo} command to indicate progress through
the makefile:
@example
@@echo About to make distribution files
@end example
@cindex @code{-n}
@cindex @code{--just-print}
@cindex @code{--dry-run}
@cindex @code{--recon}
When @code{make} is given the flag @samp{-n} or @samp{--just-print}
it only echoes commands, it won't execute them. @xref{Options Summary,
,Summary of Options}. In this case and only this case, even the
commands starting with @samp{@@} are printed. This flag is useful for
finding out which commands @code{make} thinks are necessary without
actually doing them.
@cindex @code{-s}
@cindex @code{--silent}
@cindex @code{--quiet}
@findex .SILENT
The @samp{-s} or @samp{--silent}
flag to @code{make} prevents all echoing, as if all commands
started with @samp{@@}. A rule in the makefile for the special target
@code{.SILENT} without prerequisites has the same effect
(@pxref{Special Targets, ,Special Built-in Target Names}).
@code{.SILENT} is essentially obsolete since @samp{@@} is more flexible.@refill
@node Execution, Parallel, Echoing, Commands
@section Command Execution
@cindex commands, execution
@cindex execution, of commands
@cindex shell command, execution
@vindex @code{SHELL} @r{(command execution)}
When it is time to execute commands to update a target, they are
executed by invoking a new subshell for each command line. (In
practice, @code{make} may take shortcuts that do not affect the
results.)
@cindex @code{cd} (shell command)
@cindex shell variables, setting in commands
@cindex commands setting shell variables
@strong{Please note:} this implies that setting shell variables and
invoking shell commands such as @code{cd} that set a context local to
each process will not affect the following command lines.@footnote{On
MS-DOS, the value of current working directory is @strong{global}, so
changing it @emph{will} affect the following command lines on those
systems.} If you want to use @code{cd} to affect the next statement,
put both statements in a single command line. Then @code{make} will
invoke one shell to run the entire line, and the shell will execute
the statements in sequence. For example:
@example
foo : bar/lose
cd $(@@D) && gobble $(@@F) > ../$@@
@end example
@noindent
Here we use the shell AND operator (@code{&&}) so that if the
@code{cd} command fails, the script will fail without trying to invoke
the @code{gobble} command in the wrong directory, which could cause
problems (in this case it would certainly cause @file{../foo} to be
truncated, at least).
@menu
* Choosing the Shell:: How @code{make} chooses the shell used
to run commands.
@end menu
@node Choosing the Shell, , Execution, Execution
@subsection Choosing the Shell
@cindex shell, choosing the
@cindex @code{SHELL}, value of
@vindex SHELL
The program used as the shell is taken from the variable @code{SHELL}.
By default, the program @file{/bin/sh} is used.
If this variable is not set in your makefile, the program
@file{/bin/sh} is used as the shell.
@cindex environment, @code{SHELL} in
Unlike most variables, the variable @code{SHELL} is never set from the
environment. This is because the @code{SHELL} environment variable is
used to specify your personal choice of shell program for interactive
use. It would be very bad for personal choices like this to affect the
functioning of makefiles. @xref{Environment, ,Variables from the
Environment}.
Furthermore, when you do set @code{SHELL} in your makefile that value
is @emph{not} exported in the environment to commands that @code{make}
invokes. Instead, the value inherited from the user's environment, if
any, is exported. You can override this behavior by explicitly
exporting @code{SHELL} (@pxref{Variables/Recursion, ,Communicating
Variables to a Sub-@code{make}}), forcing it to be passed in the
environment to commands.
@vindex @code{MAKESHELL} @r{(MS-DOS alternative to @code{SHELL})}
However, on MS-DOS and MS-Windows the value of @code{SHELL} in the
environment @strong{is} used, since on those systems most users do not
set this variable, and therefore it is most likely set specifically to
be used by @code{make}. On MS-DOS, if the setting of @code{SHELL} is
not suitable for @code{make}, you can set the variable
@code{MAKESHELL} to the shell that @code{make} should use; if set it
will be used as the shell instead of the value of @code{SHELL}.
@subsubheading Choosing a Shell in DOS and Windows
@cindex shell, in DOS and Windows
@cindex DOS, choosing a shell in
@cindex Windows, choosing a shell in
Choosing a shell in MS-DOS and MS-Windows is much more complex than on
other systems.
@vindex COMSPEC
On MS-DOS, if @code{SHELL} is not set, the value of the variable
@ -3741,25 +3928,10 @@ environment or command line, you are expected to set it to the full
pathname of the shell, exactly as things are on Unix.
The effect of the above DOS-specific processing is that a Makefile that
says @samp{SHELL = /bin/sh} (as many Unix makefiles do), will work
contains @samp{SHELL = /bin/sh} (as many Unix makefiles do), will work
on MS-DOS unaltered if you have e.g.@: @file{sh.exe} installed in some
directory along your @code{PATH}.
@cindex environment, @code{SHELL} in
@vindex MAKESHELL @r{(MS-DOS alternative to @code{SHELL})}
Unlike most variables, the variable @code{SHELL} is never set from the
environment. This is because the @code{SHELL} environment variable is
used to specify your personal choice of shell program for interactive
use. It would be very bad for personal choices like this to affect the
functioning of makefiles. @xref{Environment, ,Variables from the
Environment}. However, on MS-DOS and MS-Windows the value of
@code{SHELL} in the environment @strong{is} used, since on those systems
most users do not set this variable, and therefore it is most likely set
specifically to be used by @code{make}. On MS-DOS, if the setting of
@code{SHELL} is not suitable for @code{make}, you can set the variable
@code{MAKESHELL} to the shell that @code{make} should use; this will
override the value of @code{SHELL}.
@node Parallel, Errors, Execution, Commands
@section Parallel Execution
@cindex commands, execution in parallel
@ -4128,7 +4300,7 @@ The value of the @code{make} variable @code{SHELL} is not exported.
Instead, the value of the @code{SHELL} variable from the invoking
environment is passed to the sub-@code{make}. You can force
@code{make} to export its value for @code{SHELL} by using the
@code{export} directive, described below.
@code{export} directive, described below. @xref{Choosing the Shell}.
The special variable @code{MAKEFLAGS} is always exported (unless you
unexport it). @code{MAKEFILES} is exported if you set it to anything.
@ -5564,22 +5736,12 @@ different results from the same makefile. This is against the whole
purpose of most makefiles.
@cindex SHELL, import from environment
Such problems would be especially likely with the variable @code{SHELL},
which is normally present in the environment to specify the user's choice
of interactive shell. It would be very undesirable for this choice to
affect @code{make}. So @code{make} ignores the environment value of
@code{SHELL} (except on MS-DOS and MS-Windows, where @code{SHELL} is
usually not set. @xref{Execution, ,Special handling of SHELL on
MS-DOS}.)@refill
@cindex SHELL, export to environment
The @code{SHELL} variable is special in another way: just as the value
of the @code{make} variable @code{SHELL} is not taken from the
environment, so also it is not placed into the environment of commands
that @code{make} invokes. Instead, the value of @code{SHELL} from the
invoking environment is provided to the command. You can use
@code{export SHELL} to force the value of the @code{make} variable
@code{SHELL} to be placed in the environment of commands.
Such problems would be especially likely with the variable
@code{SHELL}, which is normally present in the environment to specify
the user's choice of interactive shell. It would be very undesirable
for this choice to affect @code{make}; so, @code{make} handles the
@code{SHELL} environment variable in a special way; see @ref{Choosing
the Shell}.@refill
@node Target-specific, Pattern-specific, Environment, Using Variables
@section Target-specific Variable Values
@ -8067,7 +8229,7 @@ retained for compatibility.
* Chained Rules:: How to use a chain of implicit rules.
* Pattern Rules:: How to define new implicit rules.
* Last Resort:: How to define commands for rules which
cannot find any.
cannot find any.
* Suffix Rules:: The old-fashioned style of implicit rule.
* Implicit Rule Search:: The precise algorithm for applying
implicit rules.
@ -8491,7 +8653,7 @@ with spaces.
The following tables describe of some of the more commonly-used predefined
variables. This list is not exhaustive, and the default values shown here may
not be what is selected by @code{make} for your environment. To see the
not be what are selected by @code{make} for your environment. To see the
complete list of predefined variables for your instance of GNU @code{make} you
can run @samp{make -p} in a directory with no makefiles.
@ -10423,7 +10585,7 @@ The name of the system default command interpreter, usually @file{/bin/sh}.
You can set @code{SHELL} in the makefile to change the shell used to run
commands. @xref{Execution, ,Command Execution}. The @code{SHELL}
variable is handled specially when importing from and exporting to the
environment. @xref{Environment, ,Using Variable from the Environment}.
environment. @xref{Choosing the Shell}.
@item MAKESHELL

22
file.c
View file

@ -180,14 +180,16 @@ enter_file (char *name)
new->update_status = -1;
if (HASH_VACANT (f))
hash_insert_at (&files, new, file_slot);
{
new->last = new;
hash_insert_at (&files, new, file_slot);
}
else
{
/* There is already a double-colon entry for this file. */
new->double_colon = f;
while (f->prev != 0)
f = f->prev;
f->prev = new;
f->last->prev = new;
f->last = new;
}
return new;
@ -718,14 +720,18 @@ snap_deps (void)
f2->command_flags |= COMMANDS_SILENT;
}
f = lookup_file (".POSIX");
if (f != 0 && f->is_target)
posix_pedantic = 1;
f = lookup_file (".NOTPARALLEL");
if (f != 0 && f->is_target)
not_parallel = 1;
#ifndef NO_MINUS_C_MINUS_O
/* If .POSIX was defined, remove OUTPUT_OPTION to comply. */
/* This needs more work: what if the user sets this in the makefile?
if (posix_pedantic)
define_variable (STRING_SIZE_TUPLE("OUTPUT_OPTION"), "", o_default, 1);
*/
#endif
/* Remember that we've done this. */
snapped_deps = 1;
}

1
filedef.h
View file

@ -42,6 +42,7 @@ struct file
struct file *prev; /* Previous entry for same file name;
used when there are multiple double-colon
entries for the same file. */
struct file *last; /* Last entry for the same file name. */
/* File that this file was renamed to. After any time that a
file could be renamed, call `check_renamed' (below). */

93
remake.c
View file

@ -1248,70 +1248,71 @@ f_mtime (struct file *file, int search)
rehash_file (file, name);
check_renamed (file);
mtime = name_mtime (name);
/* If the result of a vpath search is -o or -W, preserve it.
Otherwise, find the mtime of the resulting file. */
if (mtime != OLD_MTIME && mtime != NEW_MTIME)
mtime = name_mtime (name);
}
}
}
{
/* Files can have bogus timestamps that nothing newly made will be
"newer" than. Updating their dependents could just result in loops.
So notify the user of the anomaly with a warning.
/* Files can have bogus timestamps that nothing newly made will be
"newer" than. Updating their dependents could just result in loops.
So notify the user of the anomaly with a warning.
We only need to do this once, for now. */
We only need to do this once, for now. */
if (!clock_skew_detected
&& mtime != NONEXISTENT_MTIME
&& !file->updated)
{
static FILE_TIMESTAMP adjusted_now;
if (!clock_skew_detected
&& mtime != NONEXISTENT_MTIME && mtime != NEW_MTIME
&& !file->updated)
{
static FILE_TIMESTAMP adjusted_now;
FILE_TIMESTAMP adjusted_mtime = mtime;
FILE_TIMESTAMP adjusted_mtime = mtime;
#if defined(WINDOWS32) || defined(__MSDOS__)
/* Experimentation has shown that FAT filesystems can set file times
up to 3 seconds into the future! Play it safe. */
/* Experimentation has shown that FAT filesystems can set file times
up to 3 seconds into the future! Play it safe. */
#define FAT_ADJ_OFFSET (FILE_TIMESTAMP) 3
FILE_TIMESTAMP adjustment = FAT_ADJ_OFFSET << FILE_TIMESTAMP_LO_BITS;
if (ORDINARY_MTIME_MIN + adjustment <= adjusted_mtime)
adjusted_mtime -= adjustment;
FILE_TIMESTAMP adjustment = FAT_ADJ_OFFSET << FILE_TIMESTAMP_LO_BITS;
if (ORDINARY_MTIME_MIN + adjustment <= adjusted_mtime)
adjusted_mtime -= adjustment;
#elif defined(__EMX__)
/* FAT filesystems round time to the nearest even second!
Allow for any file (NTFS or FAT) to perhaps suffer from this
brain damage. */
FILE_TIMESTAMP adjustment = (((FILE_TIMESTAMP_S (adjusted_mtime) & 1) == 0
&& FILE_TIMESTAMP_NS (adjusted_mtime) == 0)
? (FILE_TIMESTAMP) 1 << FILE_TIMESTAMP_LO_BITS
: 0);
/* FAT filesystems round time to the nearest even second!
Allow for any file (NTFS or FAT) to perhaps suffer from this
brain damage. */
FILE_TIMESTAMP adjustment = (((FILE_TIMESTAMP_S (adjusted_mtime) & 1) == 0
&& FILE_TIMESTAMP_NS (adjusted_mtime) == 0)
? (FILE_TIMESTAMP) 1 << FILE_TIMESTAMP_LO_BITS
: 0);
#endif
/* If the file's time appears to be in the future, update our
concept of the present and try once more. */
if (adjusted_now < adjusted_mtime)
{
int resolution;
FILE_TIMESTAMP now = file_timestamp_now (&resolution);
adjusted_now = now + (resolution - 1);
if (adjusted_now < adjusted_mtime)
{
/* If the file's time appears to be in the future, update our
concept of the present and try once more. */
if (adjusted_now < adjusted_mtime)
{
int resolution;
FILE_TIMESTAMP now = file_timestamp_now (&resolution);
adjusted_now = now + (resolution - 1);
if (adjusted_now < adjusted_mtime)
{
#ifdef NO_FLOAT
error (NILF, _("Warning: File `%s' has modification time in the future"),
file->name);
error (NILF, _("Warning: File `%s' has modification time in the future"),
file->name);
#else
double from_now =
(FILE_TIMESTAMP_S (mtime) - FILE_TIMESTAMP_S (now)
+ ((FILE_TIMESTAMP_NS (mtime) - FILE_TIMESTAMP_NS (now))
/ 1e9));
error (NILF, _("Warning: File `%s' has modification time %.2g s in the future"),
file->name, from_now);
double from_now =
(FILE_TIMESTAMP_S (mtime) - FILE_TIMESTAMP_S (now)
+ ((FILE_TIMESTAMP_NS (mtime) - FILE_TIMESTAMP_NS (now))
/ 1e9));
error (NILF, _("Warning: File `%s' has modification time %.2g s in the future"),
file->name, from_now);
#endif
clock_skew_detected = 1;
}
}
}
}
clock_skew_detected = 1;
}
}
}
/* Store the mtime into all the entries for this file. */
if (file->double_colon)

4
tests/ChangeLog
View file

@ -1,3 +1,7 @@
2006-02-06 Paul D. Smith <psmith@gnu.org>
* scripts/options/dash-W: Add a test for bug #15341.
2006-01-03 Paul D. Smith <psmith@gnu.org>
* scripts/variables/automatic: Add a test for bug #8154.

28
tests/scripts/options/dash-W
View file

@ -57,4 +57,32 @@ run_make_test(undef, '-W bar.x', "restarts=\ntouch foo.x\nrestarts=1\ntouch baz.
rmfiles('foo.x', 'bar.x');
# Test -W on vpath-found files: it should take effect.
# Savannah bug # 15341
mkdir('x-dir');
utouch(-20, 'x-dir/x');
touch('y');
run_make_test('
y: x ; @echo cp $< $@
',
'-W x-dir/x VPATH=x-dir',
'cp x-dir/x y');
# Make sure ./ stripping doesn't interfere with the match.
run_make_test('
y: x ; @echo cp $< $@
',
'-W ./x-dir/x VPATH=x-dir',
'cp x-dir/x y');
run_make_test(undef,
'-W x-dir/x VPATH=./x-dir',
'cp ./x-dir/x y');
unlink(qw(y x-dir/x));
rmdir('x-dir');
1;

36
vpath.c
View file

@ -466,11 +466,27 @@ selective_vpath_search (struct vpath *path, char **file,
In December 1993 I loosened this restriction to allow a file
to be chosen if it is mentioned as a target in a makefile. This
seem logical. */
seem logical.
Special handling for -W / -o: make sure we preserve the special
values here. Actually this whole thing is a little bogus: I think
we should ditch the name/hname thing and look into the renamed
capability that already exists for files: that is, have a new struct
file* entry for the VPATH-found file, and set the renamed field if
we use it.
*/
{
struct file *f = lookup_file (name);
if (f != 0)
exists = not_target || f->is_target;
{
exists = not_target || f->is_target;
if (exists && mtime_ptr
&& (f->last_mtime == OLD_MTIME || f->last_mtime == NEW_MTIME))
{
*mtime_ptr = f->last_mtime;
mtime_ptr = 0;
}
}
}
if (!exists)
@ -517,6 +533,13 @@ selective_vpath_search (struct vpath *path, char **file,
exists = 0;
continue;
}
/* Store the modtime into *MTIME_PTR for the caller. */
if (mtime_ptr != 0)
{
*mtime_ptr = FILE_TIMESTAMP_STAT_MODTIME (name, st);
mtime_ptr = 0;
}
}
/* We have found a file.
@ -524,13 +547,10 @@ selective_vpath_search (struct vpath *path, char **file,
*file = savestring (name, (n + 1 - name) + flen);
/* If we get here and mtime_ptr hasn't been set, record
UNKNOWN_MTIME to indicate this. */
if (mtime_ptr != 0)
/* Store the modtime into *MTIME_PTR for the caller.
If we have had no need to stat the file here,
we record UNKNOWN_MTIME to indicate this. */
*mtime_ptr = (exists_in_cache
? FILE_TIMESTAMP_STAT_MODTIME (name, st)
: UNKNOWN_MTIME);
*mtime_ptr = UNKNOWN_MTIME;
free (name);
return 1;