Mail Archives: djgpp/1992/08/28/12:11:22

Date: Fri, 28 Aug 92 10:44:18 -0500
From: rcharif AT math DOT utexas DOT edu
Posted-Date: Fri, 28 Aug 92 10:44:18 -0500
To: jon AT halsp DOT hitachi DOT com
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: gcc environment variables
Reply-To: rcharif AT math DOT utexas DOT edu


Concerning gcc environment variables, the specs file can be used to
replace these variables. It is loaded by gcc each time it is invoked.
You will need to keep the env variable pointing to the lib path.

The include files defines can be put in the *cpp or *predefines
section.  gcc.c can be easily patched to add new defines to point to
other locations like tmp directories. This might be less work than
creating a gcc.cfg file.

This is the description of the specs file syntaxe from the file gcc.c :

/* Specs are strings containing lines, each of which (if not blank)
is made up of a program name, and arguments separated by spaces.
The program name must be exact and start from root, since no path
is searched and it is unreliable to depend on the current working directory.
Redirection of input or output is not supported; the subprograms must
accept filenames saying what files to read and write.

In addition, the specs can contain %-sequences to substitute variable text
or for conditional text.  Here is a table of all defined %-sequences.
Note that spaces are not generated automatically around the results of
expanding these sequences; therefore, you can concatenate them together
or with constant text in a single argument.

 %%	substitute one % into the program name or argument.
 %i     substitute the name of the input file being processed.
 %b     substitute the basename of the input file being processed.
	This is the substring up to (and not including) the last period
	and not including the directory.
 %g     substitute the temporary-file-name-base.  This is a string chosen
	once per compilation.  Different temporary file names are made by
	concatenation of constant strings on the end, as in `%g.s'.
	%g also has the same effect of %d.
 %d	marks the argument containing or following the %d as a
	temporary file name, so that that file will be deleted if CC exits
	successfully.  Unlike %g, this contributes no text to the argument.
 %w	marks the argument containing or following the %w as the
	"output file" of this compilation.  This puts the argument
	into the sequence of arguments that %o will substitute later.
	like %{...} but mark last argument supplied within
	as a file to be deleted on failure.
 %o	substitutes the names of all the output files, with spaces
	automatically placed around them.  You should write spaces
	around the %o as well or the results are undefined.
	%o is for use in the specs for running the linker.
	Input files whose names have no recognized suffix are not compiled
	at all, but they are included among the output files, so they will
	be linked.
 %p	substitutes the standard macro predefinitions for the
	current target machine.  Use this when running cpp.
 %P	like %p, but puts `__' before and after the name of each macro.
	(Except macros that already have __.)
	This is for ANSI C.
 %I	Substitute a -iprefix option made from GCC_EXEC_PREFIX.
 %s     current argument is the name of a library or startup file of some sort.
        Search for that file in a standard list of directories
	and substitute the full name found.
 %eSTR  Print STR as an error message.  STR is terminated by a newline.
        Use this when inconsistent options are detected.
 %x{OPTION}	Accumulate an option for %X.
 %X	Output the accumulated linker options specified by compilations.
 %Y	Output the accumulated assembler options specified by compilations.
 %a     process ASM_SPEC as a spec.
        This allows config.h to specify part of the spec for running as.
 %A	process ASM_FINAL_SPEC as a spec.  A capital A is actually
	used here.  This can be used to run a post-processor after the
	assembler has done it's job.
 %D	Dump out a -L option for each directory in library_prefix,
	followed by a -L option for each directory in startfile_prefix.
 %l     process LINK_SPEC as a spec.
 %L     process LIB_SPEC as a spec.
 %S     process STARTFILE_SPEC as a spec.  A capital S is actually used here.
 %E     process ENDFILE_SPEC as a spec.  A capital E is actually used here.
 %c	process SIGNED_CHAR_SPEC as a spec.
 %C     process CPP_SPEC as a spec.  A capital C is actually used here.
 %1	process CC1_SPEC as a spec.
 %2	process CC1PLUS_SPEC as a spec.
 %*	substitute the variable part of a matched option.  (See below.)
	Note that each comma in the substituted string is replaced by
	a single space.
 %{S}   substitutes the -S switch, if that switch was given to CC.
	If that switch was not specified, this substitutes nothing.
	Here S is a metasyntactic variable.
 %{S*}  substitutes all the switches specified to CC whose names start
	with -S.  This is used for -o, -D, -I, etc; switches that take
	arguments.  CC considers `-o foo' as being one switch whose
	name starts with `o'.  %{o*} would substitute this text,
	including the space; thus, two arguments would be generated.
 %{S*:X} substitutes X if one or more switches whose names with -S are
	specified to CC.  Note that the tail part of the -S option
	(i.e. the part matched by the `*') will be substituted for each
	occurrence of %* within X.
 %{S:X} substitutes X, but only if the -S switch was given to CC.
 %{!S:X} substitutes X, but only if the -S switch was NOT given to CC.
 %{|S:X} like %{S:X}, but if no S switch, substitute `-'.
 %{|!S:X} like %{!S:X}, but if there is an S switch, substitute `-'.
 %{.S:X} substitutes X, but only if processing a file with suffix S.
 %{!.S:X} substitutes X, but only if NOT processing a file with suffix S.
 %(Spec) processes a specification defined in a specs file as *Spec:
 %[Spec] as above, but put __ around -D arguments

The conditional text X in a %{S:X} or %{!S:X} construct may contain
other nested % constructs or spaces, or even newlines.  They are
processed as usual, as described above.

The character | is used to indicate that a command should be piped to
the following command, but only if -pipe is specified.

Note that it is built into CC which switches take arguments and which
do not.  You might think it would be useful to generalize this to
allow each compiler's spec to say which switches take arguments.  But
this cannot be done in a consistent fashion.  CC cannot even decide
which input files have been specified without knowing which switches
take arguments, and it must know which input files to compile in order
to tell which compilers to run.

CC also knows implicitly that arguments starting in `-l' are to be
treated as compiler output files, and passed to the linker in their
proper position among the other output files.  */

---- Current specs file in the lib directory ----------------------


-D__GO32__ -D__MSDOS__ -DGO32 -DMSDOS -noprecomp





%{g*:-lg} %{!p:%{!pg:-lc}}%{p:-lc_p}%{pg:-lc_p}




-Dunix -Di386



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