macOS Creating Shared Libraries [Mac][c++]

[birchy]

Hi there,

I'm trying to create and use a simple shared library on Mac OS X.
I realize that the procedure is different for Linux/Mac OS X, and I have used Google to get to the point where I can create the dylib, but when I try and link it in from another application I get the error message "ld: library not found for -lbLib". I'm probably doing something really small wrong:

Here is my lib Makefile:

# Common Variables...
ECHO = @/bin/echo
SRCDIR = src
OBJDIR = obj
INCDIR = include

# Specify compiler and compile options
CC = g++
LDCC = g++

LIBNAME=bLib
LIBVER=1.0.0
LIBEXT=dylib
LIBFULLNAME=$(LIBNAME).$(LIBEXT)
LIB_INSTALL_PATH=/usr/local/lib

# Create object files first and show all warnings
CFLAGS = -fPIC -g -c -Wall
LDFLAGS = -dynamiclib -current_version $(LIBVER) -install_name $(LIB_INSTALL_PATH)/$(LIBFULLNAME)

# Look for headers in the following dirs
#  Please ln -s to your appropriate versions (of gtk, glib)
LOCAL_INCLUDE = -I $(INCDIR)
CPOSTFLAGS = $(LOCAL_INCLUDE)

# Figure out which .o files should exist
HEADERS=$(shell ls $(INCDIR)/*.h 2> /dev/null)
SOURCES=$(shell ls $(SRCDIR)/*.cpp 2> /dev/null)
OBJECTS=$(shell ls $(SRCDIR)/*.cpp 2> /dev/null | sed -e 's/$(SRCDIR)\(.*\)\.cpp/\$(OBJDIR)\1.o/g')
LIBRARY=$(LIBFULLNAME)

ifeq ($(shell uname),Darwin)
    OS_LDPF = -framework Cocoa

    CFLAGS += -x objective-c++
endif

# Search for the specified libraries when linking
LDPOSTFLAGS = $(OS_LDPF)

# Remove the default suffixes and define our own suffix list
.SUFFIXES:
.SUFFIXES: .cpp .c .o

# Default target
all: $(LIBRARY)

# Link the binary using new object files
$(LIBRARY): $(OBJECTS)
	$(LDCC) $(LDFLAGS) $(OBJECTS) $(MAINO) $(LDPOSTFLAGS) -o $@

# Create .o files for each .cpp file in $(SRCDIR) and move it to $(OBJDIR)
$(OBJDIR)/%.o : $(SRCDIR)/%.cpp $(INCDIR)/%.h
	$(CC) $(CFLAGS) $< $(CPOSTFLAGS) -o $@

# Remove (RM = rm -f) all .o files and the executable
clean:
	$(ECHO) -n "Cleaning... "
	@$(RM) $(LIBRARY)
	@$(RM) $(OBJDIR)/*.o
	$(ECHO) Done.

install: all
	sudo mv $(LIBRARY) $(LIB_INSTALL_PATH)/$(LIBRARY)

Here is the output of a compile/link:

birchy-mac: make install
g++ -fPIC -g -c -Wall -x objective-c++ src/bPath.cpp -I include -o obj/bPath.o
g++ -dynamiclib -current_version 1.0.0 -install_name /usr/local/lib/bLib.dylib obj/bPath.o  -framework Cocoa -o bLib.dylib
sudo mv bLib.dylib /usr/local/lib/bLib.dylib
birchy-mac: ls /usr/local/lib | grep bLib
-rwxr-xr-x  1 birchy  staff     10016  7 Aug 00:28 bLib.dylib
birchy-mac: otool -D /usr/local/lib/bLib.dylib 
/usr/local/lib/bLib.dylib:
/usr/local/lib/bLib.dylib

Here is the other Makefile for another app that needs to use the .dylib library I have created. Notice the "-L/usr/local/lib -lbLib"

# Common Variables...
ECHO = @/bin/echo
SRCDIR = src
OBJDIR = obj
BINDIR = bin
INCDIR = include

# Specify compiler and compile options
CC = g++
LDCC = g++

# Create object files first and show all warnings
CFLAGS = -c -Wall -g
LDFLAGS =

# Look for headers in the following dirs
#  Please ln -s to your appropriate versions (of gtk, glib)
LOCAL_INCLUDE = -I $(INCDIR)
BLIB_INCLUDE = -I /usr/local/include/bLib
CPOSTFLAGS = $(LOCAL_INCLUDE) $(BLIB_INCLUDE)

# Figure out which .o files should exist
HEADERS=$(shell ls $(INCDIR)/*.h 2> /dev/null)
SOURCES=$(shell ls $(SRCDIR)/*.cpp 2> /dev/null)
OBJECTS=$(shell ls $(SRCDIR)/*.cpp 2> /dev/null | sed -e 's/$(SRCDIR)\(.*\)\.cpp/\$(OBJDIR)\1.o/g')
MAINSRC=main.cpp
MAINO=$(OBJDIR)/main.o
EXECUTABLE=$(BINDIR)/d

ifeq ($(shell uname),Darwin)
    OS_LDPF = -framework Cocoa

    CFLAGS += -x objective-c++
endif

# Search for the specified libraries when linking
BLIB_LIBS = -lbLib
BLIB_LDPF = -L/usr/local/lib $(BLIB_LIBS)
LDPOSTFLAGS = $(OS_LDPF) $(BLIB_LDPF)

# Remove the default suffixes and define our own suffix list
.SUFFIXES:
.SUFFIXES: .cpp .c .o

# Default target
all: $(EXECUTABLE)

# Link the binary using new object files
$(EXECUTABLE): $(OBJECTS) $(MAINO)
	$(LDCC) $(LDFLAGS) $(OBJECTS) $(MAINO) $(LDPOSTFLAGS) -o $@

# Remake main.o whenever main.cpp or a header changes
$(MAINO): $(MAINSRC) $(HEADERS)
	$(CC) $(CFLAGS) $< $(CPOSTFLAGS) -o $@

# Create .o files for each .cpp file in $(SRCDIR) and move it to $(OBJDIR)
$(OBJDIR)/%.o : $(SRCDIR)/%.cpp $(INCDIR)/%.h
	$(CC) $(CFLAGS) $< $(CPOSTFLAGS) -o $@

# Remove (RM = rm -f) all .o files and the executable
clean:
	$(ECHO) -n "Cleaning... "
	@$(RM) $(EXECUTABLE)
	@$(RM) $(OBJDIR)/*.o
	$(ECHO) Done.

# Make and run
run: all
	./$(EXECUTABLE)

# Make and debug
debug: all
	gdb $(EXECUTABLE)

And finally, here is the error message I'm getting upon compiling the app:

birchy-mac: make
g++ -c -Wall -g -x objective-c++ main.cpp -I include -I /usr/local/include/bLib -o obj/main.o
g++   obj/main.o -framework Cocoa -L/usr/local/lib -lbLib -o bin/d
ld: library not found for -lbLib
collect2: ld returned 1 exit status
make: *** [bin/d] Error 1

I'm at a loss for why this is happening.
Everything I've seen on Google says I'm creating the dylib properly.
Do I need to install it or something, like in Linux, so my library cache is updated or something?

Thanks in advance!
-Birchy

 

[smith3134]

Shared libraries are libraries that are loaded by programs when they start. When a shared library is installed properly, all programs that start afterwards automatically use the new shared library. Every shared library has a special name soname. The soname has the prefix "lib'', the name of the library, the phrase "so'', followed by a period and a version number which is incremented whenever the interface changes may occur.

 

[birchy]

The soname has the prefix "lib''

Omg, that was my mistake... I needed to prefix "lib" to my library name...
Thanks smith! It must be time for me to go to bed