Thank you for the answer but I use GNU Automake to build my Makefile automatically. So, I can't set the good argument order easily.
My Makefile.am : bin_PROGRAMS = xmlparsefile xmlparsefile_SOURCES = main.c xmlparsefile_LDFLAGS = `xml2-config --libs` xmlparsefile_CFLAGS = -Wall -Wextra `xml2-config --cflags` I think it's strange that GNU Automake do this choice if this is not compatible with most Unix linkers... I will ask the GNU Automake mailing list to know if there is a way to set a different argument order than the default. Any other suggestion is welcome. ----- Mail original ----- De: "Csaba Raduly" <rcs...@gmail.com> À: "spam spam spam spam" <spam.spam.spam.s...@free.fr> Cc: xml@gnome.org Envoyé: Vendredi 17 Février 2012 09:55:52 Objet: Re: [xml] The order of arguments when compiling Hi spam, On Thu, Feb 16, 2012 at 4:01 PM, wrote: > Hello, > > On a first computer, when I compile a C program using the libxml2 library I > do : > $ gcc `xml2-config --cflags` `xml2-config --libs` main.c > or > $ gcc main.c `xml2-config --cflags` `xml2-config --libs` > And it works (but the first method is better because it respects the order of > arguments in the gcc manual). > > On a second computer, if I compile like this, there is an error : > $ gcc `xml2-config --cflags` `xml2-config --libs` main.c > /tmp/cc7uNwed.o: In function `parseDoc': > main.c:(.text+0xd): undefined reference to `xmlParseFile' > main.c:(.text+0x51): undefined reference to `xmlCleanupParser' > main.c:(.text+0x63): undefined reference to `xmlFreeDoc' > main.c:(.text+0x68): undefined reference to `xmlCleanupParser' > collect2: ld returned 1 exit status > But if I compile like this, there is no error : > $ gcc main.c `xml2-config --cflags` `xml2-config --libs` > > I thought this was a gcc problem but someone on the gcc mailing-list tell me > that probably I have compiled libxml2 on the second computer "statically". > And I should compile it "dynamically". It's true that on the second computer, > I have compiled myself the library (configure, make, make install). On the > first computer, this is my distro package. > > How should I compile libxml2 on the 2nd computer to have the same behavior on > the two computers? You shouldn't; just use the last compilation command (with `xml2-config --libs` at the end). Most Unix linkers are one-pass; because of this, an object which needs a symbol must appear before the object (or library) which supplies that symbol. See for example http://webpages.charter.net/ppluzhnikov/linker.html GNU make's built-in rule for linking boils down to: %: %.c # commands to execute (built-in): $(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) $(TARGET_ARCH) $^ $(LOADLIBES) $(LDLIBS) -o $@ %: %.o $(CC) $(LDFLAGS) $(TARGET_ARCH) $^ $(LOADLIBES) $(LDLIBS) -o $@ As you can see, the list of source or object files ($^) is always _before_ the list of libraries (in $(LDLIBS) or $(LOADLIBES) ). Hope this helps, Csaba -- GCS a+ e++ d- C++ ULS$ L+$ !E- W++ P+++$ w++$ tv+ b++ DI D++ 5++ The Tao of math: The numbers you can count are not the real numbers. Life is complex, with real and imaginary parts. "Ok, it boots. Which means it must be bug-free and perfect. " -- Linus Torvalds "People disagree with me. I just ignore them." -- Linus Torvalds _______________________________________________ xml mailing list, project page http://xmlsoft.org/ xml@gnome.org http://mail.gnome.org/mailman/listinfo/xml
