diff options
Diffstat (limited to 'make.texinfo')
| -rw-r--r-- | make.texinfo | 51 |
1 files changed, 39 insertions, 12 deletions
diff --git a/make.texinfo b/make.texinfo index 7605994b..45de7630 100644 --- a/make.texinfo +++ b/make.texinfo @@ -6025,13 +6025,13 @@ $(call @var{variable},@var{param},@var{param},@dots{}) @end example When @code{make} expands this function, it assigns each @var{param} to -temporary variables @var{$(1)}, @var{$(2)}, etc. The variable -@var{$(0)} will contain @var{variable}. There is no maximum number of +temporary variables @code{$(1)}, @code{$(2)}, etc. The variable +@code{$(0)} will contain @var{variable}. There is no maximum number of parameter arguments. There is no minimum, either, but it doesn't make sense to use @code{call} with no parameters. Then @var{variable} is expanded as a @code{make} variable in the context -of these temporary assignments. Thus, any reference to @var{$(1)} in +of these temporary assignments. Thus, any reference to @code{$(1)} in the value of @var{variable} will resolve to the first @var{param} in the invocation of @code{call}. @@ -6050,7 +6050,7 @@ Some examples may make this clearer. This macro simply reverses its arguments: @smallexample -reverse = $2 $1 +reverse = $(2) $(1) foo = a b bar = $(call reverse,$(foo)) @@ -6063,7 +6063,7 @@ This one is slightly more interesting: it defines a macro to search for the first instance of a program in @code{PATH}: @smallexample -pathsearch = $(firstword $(wildcard $(addsufix /$1,$(subst :, ,$(PATH))))) +pathsearch = $(firstword $(wildcard $(addsufix /$(1),$(subst :, ,$(PATH))))) LS := $(call pathsearch,ls) @end smallexample @@ -6072,12 +6072,12 @@ LS := $(call pathsearch,ls) Now the variable LS contains @code{/bin/ls} or similar. The @code{call} function can be nested. Each recursive invocation gets -its own local values for @var{$(1)}, etc. that mask the values of +its own local values for @code{$(1)}, etc. that mask the values of higher-level @code{call}. For example, here is an implementation of a @dfn{map} function: @smallexample -map = $(foreach a,$2,$(call $1,$a)) +map = $(foreach a,$(2),$(call $(1),$(a))) @end smallexample Now you can @var{map} a function that normally takes only one argument, @@ -9280,8 +9280,8 @@ and concatenate the results.@* @item $(call @var{var},@var{param},@dots{}) -Evaluate the variable @var{var} replacing any references to @var{$(1)}, -@var{$(2)} with the first, second, etc. @var{param} values.@* +Evaluate the variable @var{var} replacing any references to @code{$(1)}, +@code{$(2)} with the first, second, etc. @var{param} values.@* @xref{Call Function, ,The @code{call} Function}. @end table @@ -9444,6 +9444,7 @@ but the rule in the makefile was prefixed with the @code{-} special character, so @code{make} ignored the error. @item missing separator. Stop. +@itemx missing separator (did you mean TAB instead of 8 spaces?). Stop. This means that @code{make} could not understand much of anything about the command line it just read. GNU @code{make} looks for various kinds of separators (@code{:}, @code{=}, TAB characters, etc.) to help it @@ -9453,8 +9454,10 @@ find a valid one. One of the most common reasons for this message is that you (or perhaps your oh-so-helpful editor, as is the case with many MS-Windows editors) have attempted to indent your command scripts with spaces instead of a -TAB character. Remember that every line in the command script must -begin with a TAB character. Eight spaces do not count. @xref{Rule Syntax}. +TAB character. In this case, @code{make} will use the second form of +the error above. Remember that every line in the command script must +begin with a TAB character. Eight spaces do not count. @xref{Rule +Syntax}. @item commands commence before first target. Stop. @itemx missing rule before commands. Stop. @@ -9501,7 +9504,7 @@ which already has been defined to have commands, this warning is issued and the second set of commands will overwrite the first set. @xref{Multiple Rules, ,Multiple Rules for One Target}. -@item Circular @var{xxx} <- @var{yyy} prerequisite dropped. +@item Circular @var{xxx} <- @var{yyy} dependency dropped. This means that @code{make} detected a loop in the dependency graph: after tracing the prerequisite @var{yyy} of target @var{xxx}, and its prerequisites, etc., one of them depended on @var{xxx} again. @@ -9531,6 +9534,30 @@ there are multiple patterns in the target section, and the third means the target doesn't contain a pattern character (@code{%}). @xref{Static Usage, ,Syntax of Static Pattern Rules}. +@item warning: -jN forced in submake: disabling jobserver mode. +This warning and the next are generated if @code{make} detects error +conditions related to parallel processing on systems where +sub-@code{make}s can communicate (@pxref{Options/Recursion, +,Communicating Options to a Sub-@code{make}}). This warning is +generated if a recursive invocation of a @code{make} process is forced +to have @samp{-j@var{N}} in its argument list (where @var{N} is greater +than one). This could happen, for example, if you set the @code{MAKE} +environment variable to @samp{make -j2}. In this case, the +sub-@code{make} doesn't communicate with other @code{make} processes and +will simply pretend it has two jobs of its own. + +@item warning: jobserver unavailable: using -j1. Add `+' to parent make rule. +In order for @code{make} processes to communicate, the parent will pass +information to the child. Since this could result in problems if the +child process isn't actually a @code{make}, the parent will only do this +if it thinks the child is a @code{make}. The parent uses the normal +algorithms to determine this (@pxref{MAKE Variable, ,How the @code{MAKE} +Variable Works}). If the makefile is constructed such that the parent +doesn't know the child is a @code{make} process, then the child will +receive only part of the information necessary. In this case, the child +will generate this warning message and proceed with its build in a +sequential manner. + @end table @node Complex Makefile, Concept Index, Make Errors, Top |