header file (.h) include problems with gcc

Question

I'm trying to use libxml2 to parse some XML files in C. To do this, after installing libxml2 developer package, I included this lines in my code.c file:

#include <libxml2/libxml/parser.h>
#include <libxml2/libxml/tree.h>

Ok, so far so good... But when I compile the code,

gcc ../src/code.c -o App

I got this message by gcc:

/usr/local/include/libxml2/libxml/parser.h:15:31: fatal error: libxml/xmlversion.h: No such file or directory
#include <libxml/xmlversion.h>
                             ^
compilation terminated.

The parser.h file included in my code.c, isn´t finding your include path "libxml/xmlversion.h", and I got the error message.

I tried to compile passing the library path with the -I parameter, without success.

Please guys, how can I solve this?

Show your exact compilation command. I guess that some `-I` are missing, and probably `$(pkg-config --cflags libxml-2.0)` — Basile Starynkevitch, Aug 26 '14 at 13:28
Need more information to help, how are you compiling it? Makefile? What is the build instruction that is failing? — Jonatan Goebel, Aug 26 '14 at 13:28
Please **edit your question** to put relevant details. If on Linux, install the *libxml2* development package. — Basile Starynkevitch, Aug 26 '14 at 13:35
@Constantinvs: You have a linker issue, add `$(pkg-config --libs --cflags libxml-2.0)` to your compile command, to tell the linker where the libxml headers are located. — Elias Van Ootegem, Aug 26 '14 at 13:37
@EliasVanOotegem: not a linker issue, a compiler one. He'll get the linker issue later! — Basile Starynkevitch, Aug 26 '14 at 13:41
@Constantinvs: use the `gcc -C -E` command to get proprocessed output; and add `-H` to your compilation commands to understand what is successfully included. — Basile Starynkevitch, Aug 26 '14 at 13:42
Thank you @BasileStarynkevitch, I added the `$(pkg-config --libs --cflags libxml-2.0)` to my compile command and I didn´t have the error anymore. — Constantinvs, Aug 26 '14 at 13:46
Edit your question again to show the exact compilation commands you are using.... — Basile Starynkevitch, Aug 26 '14 at 13:47

score 1 · Answer 1 · answered Aug 26 '14 at 13:54

1

Change

#include <libxml2/libxml/parser.h>
#include <libxml2/libxml/tree.h>

to

#include <libxml/parser.h>
#include <libxml/tree.h>

and add the option -I/usr/local/include/libxml2 to the command you use for compiling.

answered Aug 26 '14 at 13:54

alk

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score 1 · Accepted Answer · edited May 23 '17 at 10:33

Actually, if the libxml2 is the system one (development package), it is probably known to pkg-config so the right way to compile and link (a single source file program) is:

 gcc -Wall -g $(pkg-config --cflags libxml-2.0) \
     ../src/code.c \
     $(pkg-config --libs libxml-2.0) \
     -o App

Of course you'll need to simply #include <libxml/parser.h> etc... as answered by alk

You really should use GNU make and have your Makefile, see this example (to adapt to C instead of C++, so CFLAGS instead of CXXFLAGS and CC instead of CXX...)

^{Take the habit to always compile with all warnings -Wall and debug info -g at least during the development phase.}

header file (.h) include problems with gcc

2 Answers2