Chetan,
Am Freitag 30 Januar 2009 06:07:19 schrieb Chetan Murthy:
> I am having trouble getting my application that is statically linked
> against a rendering library to work on an ARM platform running uclinux.
> After some searching and debugging, I isolated the problem to be due some
> missing ctor symbols.
Ah, yes. This is a long-lasting bug in uCLinux.
Global static constructors are initialized from uClibc, at programm startup
time, with a weak reference symbol. The code is in crtbegin.o and crtend.o.
crtbegin must be the FIRST object in the list of linked files. At the end of
crtbegin, a section with the list of global constructor is opened. crtend.o
must be the LAST object in the list of linked files/libs. At the beginning of
crtend, the section is closed with an end marker. Each object/library which
has static constructors adds an entry to this list, and crtbegin and crtend do
the embracement magic.
The linking of crtbegin and crtend is disabled with --no-stdlibs. In the "old"
uClinux distributions, this switch is embedded in ucfront.
The quick fix is to include these files per hand like this:
# Definitions for the inclusion of static constructors
CRTBEGIN := $(shell $(CXX) $(CXXFLAGS) -print-file-name=crtbegin.o)
CRTEND := $(shell $(CXX) $(CXXFLAGS) -print-file-name=crtend.o)
# This is the rule that builds(links) the executable.
# CXX: name of the c++ compiler, set by environment
# CRTBEGIN/CRTEND: enclosure for inclusion of static constructors.
# CRTBEGIN must be the first link object
# CRTEND must be the last link object
# LDFLAGS: common flags for the linker
# CXXLIBS: needed libraries for C++ programs, including uClibc++
# LDLIBS: standard c libraries
$(EXEC): $(OBJS)
$(CXX) -o $@ $(CRTBEGIN) $(LDFLAGS) $(OBJS) $(CXXLIBS) $(LDLIBS)
$(CRTEND)
regards
Wolfgang
--
Wahre Worte sind nicht schön. Schöne Worte sind nicht wahr.
(Laotse)
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