make out-of-tree building more robust by removing the command line option for source directory

4 files changed, 54 insertions, 37 deletions

diff --git a/Makefile b/Makefile
index 42f869c..90979bc 100644
--- a/Makefile
+++ b/Makefile
@@ -11,41 +11,43 @@ LD=$(CC)
 CFLAGS=-Wall -Wextra -Wpedantic -Werror -g
 LDFLAGS=
 LDLIBS=
+SRCDIR=.
+OBJDIR=.
 
 all: maje
 
 clean:
 	rm -f maje *.o
 
-maje: includes.o
-includes.o: maje.h
-includes.o: includes.c
-	$(CC) $(CFLAGS) -c includes.c
+maje: $(OBJDIR)/includes.o
+$(OBJDIR)/includes.o: $(SRCDIR)/maje.h
+$(OBJDIR)/includes.o: $(SRCDIR)/includes.c
+	$(CC) $(CFLAGS) -o $@ -c $(SRCDIR)/includes.c
 
-maje: list.o
-list.o: maje.h
-list.o: list.c
-	$(CC) $(CFLAGS) -c list.c
+maje: $(OBJDIR)/list.o
+$(OBJDIR)/list.o: $(SRCDIR)/maje.h
+$(OBJDIR)/list.o: $(SRCDIR)/list.c
+	$(CC) $(CFLAGS) -o $@ -c $(SRCDIR)/list.c
 
-maje: main.o
-main.o: maje.h
-main.o: main.c
-	$(CC) $(CFLAGS) -c main.c
+maje: $(OBJDIR)/main.o
+$(OBJDIR)/main.o: $(SRCDIR)/maje.h
+$(OBJDIR)/main.o: $(SRCDIR)/main.c
+	$(CC) $(CFLAGS) -o $@ -c $(SRCDIR)/main.c
 
-maje: maje.o
-maje.o: maje.h
-maje.o: maje.c
-	$(CC) $(CFLAGS) -c maje.c
+maje: $(OBJDIR)/maje.o
+$(OBJDIR)/maje.o: $(SRCDIR)/maje.h
+$(OBJDIR)/maje.o: $(SRCDIR)/maje.c
+	$(CC) $(CFLAGS) -o $@ -c $(SRCDIR)/maje.c
 
-maje: make.o
-make.o: maje.h
-make.o: make.c
-	$(CC) $(CFLAGS) -c make.c
+maje: $(OBJDIR)/make.o
+$(OBJDIR)/make.o: $(SRCDIR)/maje.h
+$(OBJDIR)/make.o: $(SRCDIR)/make.c
+	$(CC) $(CFLAGS) -o $@ -c $(SRCDIR)/make.c
 
-maje: sources.o
-sources.o: maje.h
-sources.o: sources.c
-	$(CC) $(CFLAGS) -c sources.c
+maje: $(OBJDIR)/sources.o
+$(OBJDIR)/sources.o: $(SRCDIR)/maje.h
+$(OBJDIR)/sources.o: $(SRCDIR)/sources.c
+	$(CC) $(CFLAGS) -o $@ -c $(SRCDIR)/sources.c
 
 maje:
-	$(LD) $(LDFLAGS) -o $@ *.o $(LDLIBS)
+	$(LD) $(LDFLAGS) -o $@ $(OBJDIR)/*.o $(LDLIBS)
diff --git a/README.md b/README.md
index 43fad4f..5b8d8b2 100644
--- a/README.md
+++ b/README.md
@@ -23,12 +23,24 @@ Usage
 
 Run Maje with:
 
-    maje [-n] [dir]
+    maje [-n]
 
 By default, Maje will execute `make` when it is done creating the Makefile. Use
 the `-n` option to prevent this.
 
-By default, Maje generates a Makefile for sources in the current directory.
-You can specify a directory as a command line parameter to generate a Makefile
-to build binaries in a separate directory from the source. Maje will always
-build Makefiles and binaries in the current directory.
+Maje creates Makefiles with prefixes $(SRCDIR) and $(OBJDIR) for the source
+directory and object directory, respectively. By default these are set to
+`.` (the current directory). An out-of-tree build can be accomplished by 
+first generating the Makefile in the source directory and manually specifying
+the object directory as an option to `make`:
+
+    maje -n
+    mkdir obj
+    make OBDIR=obj
+
+Or:
+
+    maje -n
+    mkdir ../build
+    cd ../build
+    make -f ${OLDPWD}/Makefile SRCDIR=${OLDPWD}
diff --git a/maje.c b/maje.c
index 99f3f04..c67af52 100644
--- a/maje.c
+++ b/maje.c
@@ -8,7 +8,7 @@
 
 static void usage(char *progname)
 {
-	printf("usage: %s [-n] [dir]\n", progname);
+	printf("usage: %s [-n]\n", progname);
 }
 
 int main(int argc, char *argv[])
@@ -29,7 +29,7 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	if (optind < argc - 1) {
+	if (optind < argc) {
 		fprintf(stderr, "maje: extra operands\n");
 		return 1;
 	}
diff --git a/make.c b/make.c
index f926dd5..7047ff9 100644
--- a/make.c
+++ b/make.c
@@ -20,6 +20,8 @@ static void make_header(FILE *makefile, const char *target)
 	fprintf(makefile, "CFLAGS=-Wall -Wextra -Wpedantic -Werror -g\n");
 	fprintf(makefile, "LDFLAGS=\n");
 	fprintf(makefile, "LDLIBS=\n");
+	fprintf(makefile, "SRCDIR=.\n");
+	fprintf(makefile, "OBJDIR=.\n");
 	fprintf(makefile, "\n");
 
 	fprintf(makefile, "all: %s\n\n", target);
@@ -34,12 +36,13 @@ static void add_object(FILE *makefile, const struct majefile *src, const char *t
 	char *obj = basename(fullobj);
 	obj[strlen(obj) - 1] = 'o';
 
-	fprintf(makefile, "%s: %s\n", target, obj);
+	fprintf(makefile, "%s: $(OBJDIR)/%s\n", target, obj);
 	for (struct majefile *inc = find_includes(src); inc != NULL; inc = inc->next) {
-		fprintf(makefile, "%s: %s\n", obj, inc->path);
+		fprintf(makefile, "$(OBJDIR)/%s: $(SRCDIR)/%s\n",
+			obj, inc->path);
 	}
-	fprintf(makefile, "%s: %s\n", obj, src->path);
-	fprintf(makefile, "\t$(CC) $(CFLAGS) -c %s\n\n", src->path);
+	fprintf(makefile, "$(OBJDIR)/%s: $(SRCDIR)/%s\n", obj, src->path);
+	fprintf(makefile, "\t$(CC) $(CFLAGS) -o $@ -c $(SRCDIR)/%s\n\n", src->path);
 
 	free(fullobj);
 }
@@ -58,7 +61,7 @@ void make_makefile(const char *makepath, struct majefile *sources, const char *t
 	}
 
 	fprintf(makefile, "%s:\n", target);
-	fprintf(makefile, "\t$(LD) $(LDFLAGS) -o $@ *.o $(LDLIBS)\n");
+	fprintf(makefile, "\t$(LD) $(LDFLAGS) -o $@ $(OBJDIR)/*.o $(LDLIBS)\n");
 
 	fclose(makefile);
 }