GNU make NEWS History of user-visible changes. 28 July 2010. See the end of this file for copyrights and conditions. [This is the first section of the file NEWS distributed with GNU make (http://ftp.gnu.org/pub/gnu/make), listing changes from version 3.80 in versions 3.81 and 3.82. It is a verbatim copy, but with typographic changes, except for the 3.82 section. The only changes to content are the addition of this comment and another comment in italics and square brackets near the bottom.] All changes mentioned here are more fully described in the GNU make manual, which is contained in this distribution as the file doc/make.texi. See the README file and the GNU make manual for instructions for reporting bugs. Version 3.82 A complete list of bugs fixed in this version is available here: http://sv.gnu.org/bugs/index.php?group=make&report_id=111&fix_release_id=104&set =custom * Compiling GNU make now requires a conforming ISO C 1989 compiler and standard runtime library. * WARNING: Future backward-incompatibility! Wildcards are not documented as returning sorted values, but up to and including this release the results have been sorted and some makefiles are apparently depending on that. In the next release of GNU make, for performance reasons, we may remove that sorting. If your makefiles require sorted results from wildcard expansions, use the $(sort ...) function to request it explicitly. * WARNING: Backward-incompatibility! The POSIX standard for make was changed in the 2008 version in a fundamentally incompatible way: make is required to invoke the shell as if the '-e' flag were provided. Because this would break many makefiles that have been written to conform to the original text of the standard, the default behavior of GNU make remains to invoke the shell with simply '-c'. However, any makefile specifying the .POSIX special target will follow the new POSIX standard and pass '-e' to the shell. See also .SHELLFLAGS below. * WARNING: Backward-incompatibility! The '$?' variable now contains all prerequisites that caused the target to be considered out of date, even if they do not exist (previously only existing targets were provided in $?). * WARNING: Backward-incompatibility! As a result of parser enhancements, three backward-compatibility issues exist: first, a prerequisite containing an "=" cannot be escaped with a backslash any longer. You must create a variable containing an "=" and use that variable in the prerequisite. Second, variable names can no longer contain whitespace, unless you put the whitespace in a variable and use the variable. Third, in previous versions of make it was sometimes not flagged as an error for explicit and pattern targets to appear in the same rule. Now this is always reported as an error. * WARNING: Backward-incompatibility! The pattern-specific variables and pattern rules are now applied in the shortest stem first order instead of the definition order (variables and rules with the same stem length are still applied in the definition order). This produces the usually-desired behavior where more specific
patterns are preferred. To detect this feature search for 'shortest-stem' in the .FEATURES special variable. * WARNING: Backward-incompatibility! The library search behavior has changed to be compatible with the standard linker behavior. Prior to this version for prerequisites specified using the -lfoo syntax make first searched for libfoo.so in the current directory, vpath directories, and system directories. If that didn't yield a match, make then searched for libfoo.a in these directories. Starting with this version make searches first for libfoo.so and then for libfoo.a in each of these directories in order. * New command line option: --eval=STRING causes STRING to be evaluated as makefile syntax (akin to using the $(eval ...) function). The evaluation is performed after all default rules and variables are defined, but before any makefiles are read. * New special variable: .RECIPEPREFIX allows you to reset the recipe introduction character from the default (TAB) to something else. The first character of this variable value is the new recipe introduction character. If the variable is set to the empty string, TAB is used again. It can be set and reset at will; recipes will use the value active when they were first parsed. To detect this feature check the value of $(.RECIPEPREFIX). * New special variable: .SHELLFLAGS allows you to change the options passed to the shell when it invokes recipes. By default the value will be "-c" (or "-ec" if .POSIX is set). * New special target: .ONESHELL instructs make to invoke a single instance of the shell and provide it with the entire recipe, regardless of how many lines it contains. As a special feature to allow more straightforward conversion of makefiles to use .ONESHELL, any recipe line control characters ('@', '+', or '-') will be removed from the second and subsequent recipe lines. This happens _only_ if the SHELL value is deemed to be a standard POSIX-style shell. If not, then no interior line control characters are removed (as they may be part of the scripting language used with the alternate SHELL). * New variable modifier 'private': prefixing a variable assignment with the modifier 'private' suppresses inheritance of that variable by prerequisites. This is most useful for target- and pattern-specific variables. * New make directive: 'undefine' allows you to undefine a variable so that it appears as if it was never set. Both $(flavor) and $(origin) functions will return 'undefined' for such a variable. To detect this feature search for 'undefine' in the .FEATURES special variable. * The parser for variable assignments has been enhanced to allow multiple modifiers ('export', 'override', 'private') on the same line as variables, including define/endef variables, and in any order. Also, it is possible to create variables and targets named as these modifiers. * The 'define' make directive now allows a variable assignment operator after the variable name, to allow for simple, conditional, or appending multi-line variable assignment.
Version 3.81 * GNU make is ported to OS/2. * GNU make is ported to MinGW. The MinGW build is only supported by the build_w32.bat batch file; see the file README.W32 for more details. * WARNING: Future backward-incompatibility! Up to and including this release, the '$?' variable does not contain any prerequisite that does not exist, even though that prerequisite might have caused the target to rebuild. Starting with the next release of GNU make, '$?' will contain all prerequisites that caused the target to be considered out of date. See this Savannah bug: http://savannah.gnu.org/bugs/index.php?func=detailitem&item_id=16051. * WARNING: Backward-incompatibility! GNU make now implements a generic second expansion feature on the prerequisites of both explicit and implicit (pattern) rules. In order to enable this feature, the special target '.SECONDEXPANSION' must be defined before the first target which takes advantage of it. If this feature is enabled then after all rules have been parsed the prerequisites are expanded again, this time with all the automatic variables in scope. This means that in addition to using standard SysV $$@ in prerequisites lists, you can also use complex functions such as $$(notdir $$@) etc. This behavior applies to implicit rules, as well, where the second expansion occurs when the rule is matched. However, this means that when '.SECONDEXPANSION' is enabled you must double-quote any “$” in your filenames; instead of “foo: boo$$bar” you now must write “foo: foo$$$$bar”. Note that the SysV $$@ etc. feature, which used to be available by default, is now only available when the .SECONDEXPANSION target is defined. If your makefiles take advantage of this SysV feature you will need to update them. * WARNING: Backward-incompatibility! In order to comply with POSIX, the way in which GNU make processes backslash-newline sequences in command strings has changed. If your makefiles use backslash-newline sequences inside of single-quoted strings in command scripts you will be impacted by this change. See the GNU make manual subsection Splitting Command Lines (node Splitting Lines), in section Command Syntax, chapter Writing the Commands in Rules, for details. * WARNING: Backward-incompatibility! Some previous versions of GNU make had a bug where “#” in a function invocation such as $(shell ...) was treated as a make comment. A workaround was to escape these with backslashes. This bug has been fixed: if your makefile uses “\#” in a function invocation the backslash is now preserved, so you'll need to remove it. * New command-line option: -L (--check-symlink-times). On systems that support symbolic links, if this option is given then GNU make will use the most recent modification time of any symbolic links that are used to resolve target files. The default behavior remains as it always has: use the modification time of the actual target file only. * The else conditional line can now be followed by any other valid conditional on the same line: this does not increase the depth of the conditional nesting, so only one endif is required to close the conditional. * All pattern-specific variables that match a given target are now used (previously only the first match was used). * Target-specific variables can be marked as exportable using the export keyword. * In a recursive $(call ...) context, any extra arguments from the outer call are now masked in the context of the inner call. * Implemented a solution for the thundering herd problem with “-j –l”. This version of GNU make uses an algorithm suggested by Thomas Riedl <email@example.com> to track the number of jobs started in the last second and artificially adjust GNU make's view of the system's load average accordingly.
* New special variables available in this release: – .INCLUDE_DIRS: Expands to a list of directories that make searches for included makefiles. – .FEATURES: Contains a list of special features available in this version of GNU make. – .DEFAULT_GOAL: Set the name of the default goal make will use if no goals are provided on the command line. – MAKE_RESTARTS: If set, then this is the number of times this instance of make has been restarted (see How Makefiles Are Remade in the manual). – New automatic variable: $| (added in 3.80, actually): contains all the order-only prerequisites defined for the target. * New functions available in this release: – $(lastword…) returns the last word in the list. This gives identical results as $(word $(words…)…), but is much faster. – $(abspath…) returns the absolute path (all “.” and “..” directories resolved, and any duplicate “/” characters removed) for each path provided. – $(realpath…) returns the canonical pathname for each path provided. The canonical pathname is the absolute pathname, with all symbolic links resolved as well. – $(info…) prints its arguments to stdout. No makefile name or line number info, etc. is printed. – $(flavor…) returns the flavor of a variable. – $(or…) provides a short-circuiting or conditional: each argument is expanded. The first true (non-empty) argument is returned; no further arguments are expanded. Expands to empty if there are no true arguments. – $(and…) provides a short-circuiting and conditional: each argument is expanded. The first false (empty) argument is returned; no further arguments are expanded. Expands to the last argument if all arguments are true. * Changes made for POSIX compatibility: – Only touch targets (under -t) if they have at least one command. – Setting the SHELL make variable does not change the value of the SHELL environment variable given to programs invoked by make. As an enhancement to POSIX, if you export the make variable SHELL then it will be set in the environment, just as before. * On MS Windows systems, explicitly setting SHELL to a pathname ending in cmd or cmd.exe (caseinsensitive) will force GNU make to use the DOS command interpreter in batch mode even if a UNIX-like shell could be found on the system. * On VMS there is now support for case-sensitive filesystems such as ODS5. See the readme.vms file for information. * Parallel builds (-jN) no longer require a working Bourne shell on Windows platforms. They work even with the stock Windows shells, such as cmd.exe and command.com. * Updated to autoconf 2.59, automake 1.9.5, and gettext 0.14.1. Users should not be impacted. * New translations for Swedish, Chinese (simplified), Ukrainian, Belarusian, Finnish, Kinyarwandan, and Irish. Many updated translations. A complete list of bugs fixed in this version is available here: http://savannah.gnu.org/bugs/index.php?group=make&report_id=111&fix_release_id=103.
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