1

I have linked a ".c" file to another one. ld doesn't return any error but the compiler can't find included header files in this ".c" file and returns this error:

../libvmi/driver/xen.c:27:20: fatal error: libvmi.h: No such file or directory

Here is the Makefile of my project:

## Source directory

SUBDIRS =  

INCLUDES = -I$(top_srcdir) $(top_srcdir)/libvmi
AM_LDFLAGS = -L$(top_srcdir)/libvmi/.libs/  $(top_srcdir)/libvmi/driver $(top_srcdir)/libvmi/libvmi.h
LDADD = -lvmi -lm $(LIBS)  $(top_srcdir)/libvmi/driver/xen.c $(top_srcdir)/libvmi/libvmi.h
bin_PROGRAMS = module-list process-list map-symbol map-addr dump-memory
module_list_SOURCES = module-list.c
process_list_SOURCES = process-list.c
map_symbol_SOURCES = map-symbol.c
map_addr_SOURCES = map-addr.c
dump_memory_SOURCES = dump-memory.c

As you see above I thought I should add "$(top_srcdir)/libvmi" to "INCLUDES"; this is the directory that libvmi.h is located.

The original Makefile is:

## Source directory

SUBDIRS = 

INCLUDES = -I$(top_srcdir)
AM_LDFLAGS = -L$(top_srcdir)/libvmi/.libs/
LDADD = -lvmi -lm $(LIBS)
c_sources = process-list.c $(top_srcdir)/libvmi/driver/xen.c
bin_PROGRAMS = module-list process-list map-symbol map-addr dump-memory
module_list_SOURCES = module-list.c
process_list_SOURCES = $(c_sources)
map_symbol_SOURCES = map-symbol.c
map_addr_SOURCES = map-addr.c
dump_memory_SOURCES = dump-memory.c

I have modified it to link "libvmi/driver/xen.c" to process-list.c file which are located in different directories.

This is because of something's wrong in Makefile, yes?

Improve this question

2 Answers 2

Reset to default
1

Add a -I to the path you added. Note this is a compiler, not linker question

Improve this answer
Sign up to request clarification or add additional context in comments.

Comments

0

The reason ld doesn't return an error is because it is not invoked. The error message you are getting is coming from the compiler, and the loader is not invoked until the compiler is successful.

Yes, you do need to add $(source_dir)/libvmi to INCLUDES; you just need to do it symmetrically with the existing entry:

INCLUDES = -I$(top_srcdir) -I$(top_srcdir)/libvmi

Note the -I preceding the directory name. You have a similar problem in AM_LDFLAGS and LDADD:

AM_LDFLAGS = -L$(top_srcdir)/libvmi/.libs/ -L$(top_srcdir)/libvmi/driver
LDADD = -lvmi -lm $(LIBS)

but you do not want to add the header file $(top_srcdir)/libvmi/libvmi.h to the load flags. Headers are not libraries; headers are not appropriate for sending to the linker/loader. You should only supply the linker/loader with object files, libraries, and options — no source files, no headers.

That more or less deals with the surface issues. What is the real problem you are trying to solve?

If you need to link with code from a library built in libvmi directory, why don't you make the dependency changes in this makefile to pick up the library from the libvmi directory (and separately run the build for the library in the libvmi directory)? Or, if you really want to do the compilation in the current directory (but why?), create links to the libvmi files locally (or copy them; no, on second thoughts, don't copy them), and compile them locally? Mixed directory working is painful at best — and to be avoided when possible, which it almost always is.

I note that the original makefile does in fact include -lvmi on the link line, so what I outlined is what you're expected to use. Why isn't that working for you? This is very much an XY Problem. I recommend reworking the question so that you get a solution to the real problem you started out with, rather than the artificial problem you ran into attempting to solve the real problem in a misguided way.

Improve this answer

2 Comments

I just want to use some functions of file xen.c in process-list.c,so I need to link them.First linker returned "error:undefined reference to foo function". but this error disappeared as I modified Makefile and compiler returned the error mentioned above.Now I think there is something wrong with compiling xen.c, that its included headerfiles can't be found by compiler!
Yes; it appears that xen.c is intended to be compiled in the libvmi/driver directory (or perhaps the libvmi directory), not in the current directory, so when you try to compile it in the wrong place, it doesn't find all the files it needs. So, you should either localize the code so it compiles in the current directory, or use the library from the libvmi or libvmi/driver directory.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.