On 7/19/07, Kristof Provost <address@hidden> wrote:
On 2007-07-18 22:41:26 (+0300), Or Goshen <address@hidden> wrote:
> Hi
>
> I have the following make file:
>
> TEST_LO=test.lo
>
> %.so: $($*_LO)
> $(CC) $(LDFLAGS) -shared -Wl,-soname,$*.so.0 -o $*.so $($*_LO)
>
> %.lo: %.c
> $(CC) $(CFLAGS) -fPIC -o $*.lo -c $*.c
>
>
> When I execute "make TEST.so" I get:
>
> $ make TEST.so
> gcc -shared -Wl,-soname,TEST.so.0 -o TEST.so test.lo
> gcc: test.lo: No such file or directory
> make: *** [TEST.so
> ] Error 1
>
> My question is - why doesnt it expand "$($*_LO)" in the dependencies as well ?
> (I got the file "test.c" in the directory)
Make will determine prerequisites based on the variable value when the
line is parsed, not when the target is built. That means make isn't
aware that
test.lo is a prerequisite. Try putting '@echo prereqs: $^'
before the compile statement in the %.so rule.
Fortunately GNU Make has .SECONDEXPANSION.
Read the manual, specifically this bit:
http://www.gnu.org/software/make/manual/make.html#Secondary-Expansion
You can rewrite your makefile to become:
.SECONDEXPANSION:
TEST_LO=test.lo
%.so: $$($$*_LO)
$(CC) $(LDFLAGS) -shared -Wl,-soname,address@hidden -o $@ $^
When I try to use second expansion as you suggested "make -d TEST.so" returns :
.
.
.
Considering target file `TEST.so'.
File `TEST.so' does not exist.
Looking for an implicit rule for `TEST.so'.
Trying pattern rule with stem `TEST'.
Trying rule prerequisite `$($*_LO)'.
Trying pattern rule with stem `TEST.so'.
Trying implicit prerequisite `TEST.so,v'.
Trying pattern rule with stem `TEST.so'.
Trying implicit prerequisite `RCS/TEST.so,v'.
Trying pattern rule with stem `TEST.so'.
Trying implicit prerequisite `RCS/TEST.so'.
Trying pattern rule with stem `TEST.so'.
Trying implicit prerequisite `s.TEST.so'.
Trying pattern rule with stem `TEST.so'.
Trying implicit prerequisite `SCCS/s.TEST.so'.
Trying pattern rule with stem `TEST'.
Trying rule prerequisite `$($*_LO)'.
Looking for a rule with intermediate file `$($*_LO)'.
Avoiding implicit rule recursion.
Trying pattern rule with stem `$($*_LO)'.
Trying implicit prerequisite `$($*_LO),v'.
Trying pattern rule with stem `$($*_LO)'.
Trying implicit prerequisite `RCS/$($*_LO),v'.
Trying pattern rule with stem `$($*_LO)'.
Trying implicit prerequisite `RCS/$($*_LO)'.
Trying pattern rule with stem `$($*_LO)'.
Trying implicit prerequisite `s.$($*_LO)'.
Trying pattern rule with stem `$($*_LO)'.
Trying implicit prerequisite `SCCS/s.$($*_LO)'.
No implicit rule found for `TEST.so'.
Finished prerequisites of target file `TEST.so'.
Must remake target `TEST.so'.
make: *** No rule to make target `TEST.so', needed by `all'. Stop.
%.lo: %.c
$(CC) $(CFLAGS) -fPIC -o $@ -c $<
Kristof