[英]Adding a library to autotools files does not work (linker ignores it)
I'm a dummy regarding C build tools, so I have a forked project to which I want to add a dynamically linked library: 我是C构建工具的虚拟人物,所以我有一个分支的项目,我想向其中添加动态链接的库:
https://github.com/iem-projects/ncview/tree/26c3549d165dc6047dc37db252062fd73eb9282c https://github.com/iem-projects/ncview/tree/26c3549d165dc6047dc37db252062fd73eb9282c
Basically, what I need is to include liblo
. 基本上,我需要包含
liblo
。 There is all kinds of voodoo going on for the existing libraries of the project ( netcdf
for example). 项目的现有库(例如
netcdf
)正在使用各种伏都netcdf
。
I am trying to follow this manual which basically says, I should add stuff to configure.in
and Makefile.am
, then run autoreconf
, autoconf
, and automake
, then ./configure
and finally make
. 我试图遵循该手册 , 该手册基本上说:我应该在
configure.in
和Makefile.am
添加一些内容,然后运行autoreconf
, autoconf
和automake
,然后运行./configure
并最终make
。
This I added to configure.in
: 我添加到
configure.in
:
# OSC support
PKG_CHECK_MODULES(LIBLO, liblo >= 0.26)
And this I added to Makefile.am
: 这是我添加到
Makefile.am
:
bin_PROGRAMS = ncview
ncview_LDADD = $(LIBLO_LIBS)
Now configure
is at least successfully checking for that library: 现在
configure
至少可以成功检查该库:
checking for LIBLO... yes
But make
doesn't include the library with the linker it seems: 但是
make
似乎没有包含链接器的库:
$ make
make all-recursive
Making all in src
/usr/bin/gcc-4.2 -I/usr/X11/include -g -O2 -L/opt/local/lib -lnetcdf -lSM -lICE \
-L/usr/X11/lib -R/usr/X11/lib -lX11 -L/usr/X11/lib -R/usr/X11/lib -Wl,-rpath, -o \
ncview ncview.o file.o util.o do_buttons.o file_netcdf.o view.o do_print.o \
epic_time.o interface.o x_interface.o dataedit.o display_info.o plot_xy.o utils.o \
range.o printer_options.o overlay.o filesel.o set_options.o plot_range.o udu.o \
SciPlot.o RadioWidget.o cbar.o utCalendar2_cal.o calcalcs.o colormap_funcs.o \
make_tc_data.o stringlist.o handle_rc_file.o -lm -L/opt/local/lib -lnetcdf -lXaw \
-lXt -L/usr/X11/lib -R/usr/X11/lib -lSM -lICE -L/usr/X11/lib -R/usr/X11/lib -lX11 \
-L/usr/X11/lib -R/usr/X11/lib -lpng
Undefined symbols:
"_lo_address_new", referenced from:
_main in ncview.o
"_lo_send_internal", referenced from:
_main in ncview.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
So it links the old libraries ( netcdf
, X11
), but doesn't pick up the one I added ( liblo
) 因此,它链接了旧的库(
netcdf
, X11
),但没有选择我添加的库( liblo
)
This whole makefile business is black magic to me, so any clues as to why the library doesn't get linked is welcome. 整个makefile业务对我来说都是不可思议的,因此欢迎提供任何有关为什么未链接库的线索。
Solution : 解决方案 :
The the hint of AC_SUBST
, and looking again closer at the way the other libraries were integrated, I managed to get it working. 在
AC_SUBST
的提示下,再次仔细查看其他库的集成方式,我设法使其正常工作。 Nothing had to be added to Makefile.am
. 无需添加任何内容到
Makefile.am
。 In configure.in
(aka configure.ac
), the following was added: 在
configure.in
(又名configure.ac
)中,添加了以下内容:
# OSC support
PKG_CHECK_MODULES(LIBLO, liblo >= 0.26)
LIBSsave=$LIBS
CFLAGSsave=$CFLAGS
CFLAGS=$LIBLO_CFLAGS
LIBS=$LIBLO_LIBS
# AC_MSG_CHECKING([for liblo OSC library])
# AC_MSG_RESULT()
# AC_CHECK_LIB(LIBLO,lo_address_new,[],[libloWorks=no])
echo "liblo OSC library: $LIBLO_LIBS"
AC_SUBST(LIBLO_CFLAGS) # si?
AC_SUBST(LIBLO_LIBS)
LIBS+=$LIBSsave
CFLAGS+=$CFLAGSsave
After PKG_CHECK_MODULES
, the variables LIBIO_CFLAGS
and LIBIO_LIBS
should be defined. 在
PKG_CHECK_MODULES
之后,应定义变量LIBIO_CFLAGS
和LIBIO_LIBS
。 At this point, you should add: 此时,您应该添加:
AC_SUBST(LIBIO_CFLAGS)
AC_SUBST(LIBIO_LIBS)
to the configure.ac
file. 到
configure.ac
文件。 The Makefile.am
then needs to make use of these substitutions: 然后,
Makefile.am
需要使用以下替换:
ncview_CPPFLAGS = $(LIBIO_CFLAGS)
ncview_LDADD = $(LIBIO_LIBS)
you can also directly substitute the value of LIBLO-flags with a syntax like: 您还可以使用以下语法直接替换LIBLO-flags的值:
configure.ac: configure.ac:
PKG_CHECK_MODULES(LIBLO, liblo >= 0.26)
Makefile.am: Makefile.am:
ncview_LDADD += @LIBLO_LIBS@
you should also take care not to overwrite previous values of LDADD (or the other way round, so your values get overwritten) 您还应注意不要覆盖LDADD的先前值(反之亦然,因此您的值将被覆盖)
ncview_LDADD = @LIBLO_LIBS@
ncview_LDADD = -lm
should give you a warning and @LIBLO_LIBS@ will have no effect. 应该给您一个警告,@ LIBLO_LIBS @无效。
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