I tried to link libcurl to my program but the linker tells me some errors.
I've checked that the option "-lcurl" is used.I've also checked that libcurl is installed correctly.
The command I tried is:
gdc myprogram.d -o myprogram -lcurl
And the linker told me following errors:
/usr/lib/gcc/x86_64-linux-gnu/4.8/libgphobos2.a(curl.o): In function `_D3std3net4curl4Curl18_sharedStaticCtor1FZv':
/build/buildd/gcc-4.8-4.8.2/build/x86_64-linux-gnu/libphobos/src/../../../../src/libphobos/src/std/net/curl.d:3432: undefined reference to `curl_global_init'
/usr/lib/gcc/x86_64-linux-gnu/4.8/libgphobos2.a(curl.o): In function `_D3std3net4curl4Curl8shutdownMFZv':
/build/buildd/gcc-4.8-4.8.2/build/x86_64-linux-gnu/libphobos/src/../../../../src/libphobos/src/std/net/curl.d:3561: undefined reference to `curl_easy_cleanup'
/usr/lib/gcc/x86_64-linux-gnu/4.8/libgphobos2.a(curl.o): In function `shutdown':
/build/buildd/gcc-4.8-4.8.2/build/x86_64-linux-gnu/libphobos/src/../../../../src/libphobos/src/std/net/curl.d:3561: undefined reference to `curl_easy_cleanup'
/build/buildd/gcc-4.8-4.8.2/build/x86_64-linux-gnu/libphobos/src/../../../../src/libphobos/src/std/net/curl.d:3561: undefined reference to `curl_easy_cleanup'
/build/buildd/gcc-4.8-4.8.2/build/x86_64-linux-gnu/libphobos/src/../../../../src/libphobos/src/std/net/curl.d:3561: undefined reference to `curl_easy_cleanup'
/usr/lib/gcc/x86_64-linux-gnu/4.8/libgphobos2.a(curl.o): In function `_D3std3net4curl4HTTP4Impl6__dtorMFZv':
/build/buildd/gcc-4.8-4.8.2/build/x86_64-linux-gnu/libphobos/src/../../../../src/libphobos/src/std/net/curl.d:2033: undefined reference to `curl_slist_free_all'
There are some cases using official compiler dmd but I couldn't find the case with gdc.
Any ideas?
(Ubuntu 14.02 LTS amd64)
Do you have installed
libcurl4-gnutls-dev
if yes try this:
gdc -lcurl-gnutls myprogram.d -o myprogram
Problem is with order how program is link, on Ubuntu it is important to add curl behind libgphobos so this could work:
gdc myprogram.d /usr/lib/gcc/x86_64-linux-gnu/4.8/libgphobos2.a -o myprogram `curl-config --libs`
some more details
Related
I'm working on a program in which I use PDCurses3.5 functions using i686-w64-mingw32-gcc.exe.
When I compile the program, I keep getting errors such as "undefined reference to 'COLS'", "undefined reference to 'lines'".
I have checked that <curses.h> header and the library package properly installed.
Here is my input line:
> i686-w64-mingw32-gcc.exe set.o read.o elements.o random.o
> -L../standard/test -lplotfit -lplotget -lgfortran -Wl,--subsystem,console -mwindows -o runtime/mingw/result -lm -static -lws2_32 -lpdcurses
And the first part of the error is:
../standard/bin/mingw/menu.o:menu.c:(.text+0xb): undefined reference to `COLS'
../standard/bin/mingw/menu.o:menu.c:(.text+0x16): undefined reference to `COLS'
../standard/bin/mingw/menu.o:menu.c:(.text+0x33): undefined reference to `LINES'
../standard/bin/mingw/menu.o:menu.c:(.text+0x47): undefined reference to `MOVE'
../standard/bin/mingw/menu.o:menu.c:(.text+0x74): undefined reference to `initscr'
...
It seems the program cannot refer to libpdcurses.a in its library file.
What am I doing wrong?
When you use -lpdcurses, the linker looks for libpdcurses.a in certain predefined locations, plus those specified via -L. But, by default, the library is built as pdcurses.a. To link it, you can directly specify its location; e.g.:
gcc -oprogname.exe progname.c pdcurses.a
or
gcc -oprog2.exe prog2.c /pdcurses/win32/pdcurses.a
Alternatively, you can rename the library to libpdcurses.a, and either copy it to a location in the existing search path, or use -L:
gcc -oprogname.exe progname.c -lpdcurses
or
gcc -oprog2.exe prog2.c -L/pdcurses/win32 -lpdcurses
Iam trying to compile the code example available on the libmosquitto website (at the bottom):
http://mosquitto.org/man/libmosquitto-3.html
Iam using Ubuntu 12.04 and I've installed libmosquitto1 and libmosquitto1-dev packages. Before installing them I added the mosquitto repository:
sudo apt-add-repository ppa:mosquitto-dev/mosquitto-ppa
sudo apt-get update
Iam trying to compile the example as follows:
gcc -lmosquitto mosquito.c -o mosquito
But I get the following errors:
/tmp/cc6eU8kw.o: In function `my_connect_callback':
mosquito.c:(.text+0xf8): undefined reference to `mosquitto_subscribe'
/tmp/cc6eU8kw.o: In function `main':
mosquito.c:(.text+0x298): undefined reference to `mosquitto_lib_init'
mosquito.c:(.text+0x2b4): undefined reference to `mosquitto_new'
mosquito.c:(.text+0x310): undefined reference to `mosquitto_log_callback_set'
mosquito.c:(.text+0x324): undefined reference to `mosquitto_connect_callback_set'
mosquito.c:(.text+0x338): undefined reference to `mosquitto_message_callback_set'
mosquito.c:(.text+0x34c): undefined reference to `mosquitto_subscribe_callback_set'
mosquito.c:(.text+0x364): undefined reference to `mosquitto_connect'
mosquito.c:(.text+0x3b4): undefined reference to `mosquitto_loop'
mosquito.c:(.text+0x3c8): undefined reference to `mosquitto_destroy'
mosquito.c:(.text+0x3d0): undefined reference to `mosquitto_lib_cleanup'
collect2: ld returned 1 exit status
Can someone give me some tips on how to compile this simple example?
Thanks
You have to put the -lmosquitto at the end (after the source files).
gcc mosquito.c -lmosquitto -o mosquito
# or
gcc mosquito.c -o mosquito -lmosquitto
# or
gcc -o mosquito mosquito.c -lmosquitto
Or better:
gcc -Wall -Wextra -pedantic -o mosquito mosquito.c -lmosquitto
I am trying to use Curl in C.
I visited Curl official page, and copied sample source code.
below is the link:
http://curl.haxx.se/libcurl/c/sepheaders.html
when I run this code with command "gcc test.c",
the console shows message like below.
/tmp/cc1vsivQ.o: In function `main':
test.c:(.text+0xe1): undefined reference to `curl_global_init'
test.c:(.text+0xe6): undefined reference to `curl_easy_init'
test.c:(.text+0x10c): undefined reference to `curl_easy_setopt'
test.c:(.text+0x12e): undefined reference to `curl_easy_setopt'
test.c:(.text+0x150): undefined reference to `curl_easy_setopt'
test.c:(.text+0x17e): undefined reference to `curl_easy_cleanup'
test.c:(.text+0x1b3): undefined reference to `curl_easy_cleanup'
test.c:(.text+0x1db): undefined reference to `curl_easy_setopt'
test.c:(.text+0x1e7): undefined reference to `curl_easy_perform'
test.c:(.text+0x1ff): undefined reference to `curl_easy_cleanup'
I do not know how to solve this.
You don't link with the library.
When using an external library you must link with it:
$ gcc test.c -lcurl
The last option tells GCC to link (-l) with the library curl.
In addition to Joachim Pileborg's answer, it is useful to remember that gcc/g++ linking is sensitive to order and that your linked libraries must follow the things that depend upon them.
$ gcc -lcurl test.c
will fail, missing the same symbols as before. I mention this because I came to this page for forgetting this fact.
I have the same problem, but i use g++ with a make file.
This is a linker issue.
You need to add option -lcurl on the compiler and on the linker.
In my case on the make file:
CC ?= gcc
CXX ?= g++
CXXFLAGS += -I ../src/ -I ./ -DLINUX -lcurl <- compile option
LDFLAGS += -lrt -lpthread -lcurl <- linker option
Gerard
Depending how bad things are you might need an -L/somewhere in LDFLAGS to let the linker know where the libraries are. ldconfig is supposed to pick them up and find them on every boot but on a new machine it can take a little prodding, like adding a directory to your /etc/ld.so.conf.
I have been searching for a couple of hours and found several threads with the same problem and tried all their suggestions.
My curl.h is in C:\MinGW\msys\1.0\curl-7.29.0\include\curl and I've included it at compile time but for some reason gcc claims it can't find it:
gcc -o curl.exe curl.c -IC:/MinGW/msys/1.0/local/ -IC:/MinGW/msys/1.0/curl-7.29.0/lib/.libs/ -IC:/MinGW/msys/1.0/curl-7.29.0/include/curl -IC:/MinGW/msys/1.0/OpenSSL-Win32/ -lcurl -lws2_32
and the result:
curl.c:4:32: fatal error: curl/curl.h: No such file or directory
UPDATE: (With the suggestion from H2CO3)
$ gcc -o curl.exe curl.c -IC:/MinGW/msys/1.0/local -IC:/MinGW/msys/1.0/curl-7.29.0/lib/.libs/ -IC:/MinGW/msys/1.0/curl-7.29.0/include/ -IC:/MinGW/msys/1.0/OpenSSL-Win32/include/ -lws2_32
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0xa8): undefined reference to `_imp__curl_global_init'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0xe6): undefined reference to `_imp__curl_formadd'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x124): undefined reference to `_imp__curl_formadd'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x162): undefined reference to `_imp__curl_formadd'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x169): undefined reference to `_imp__curl_easy_init'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x183): undefined reference to `_imp__curl_slist_append'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x1b8): undefined reference to `_imp__curl_easy_setopt'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x211): undefined reference to `_imp__curl_easy_setopt'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x237): undefined reference to `_imp__curl_easy_setopt'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x245): undefined reference to `_imp__curl_easy_perform'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x25e): undefined reference to `_imp__curl_easy_strerror'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x288): undefined reference to `_imp__curl_easy_cleanup'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x296): undefined reference to `_imp__curl_formfree'
C:\DOCUME~1\J10441\LOCALS~1\Temp\ccHP6WWt.o:curl.c:(.text+0x2a4): undefined reference to `_imp__curl_slist_free_all'
collect2: ld returned 1 exit status
If I try to compile with -lcurl it says ..... ld.exe: cannot find -lcurl is this because it can't find the dll?
You're including <curl/curl.h>, and not <curl.h>. So you have to tell the compiler to look for header files in the include directory, and not in include/curl:
gcc -IC:\MinGW\msys\1.0\curl-7.29.0\include etc. etc.
This might be beyond the scope of what you're doing, but, I found it best to install a version of cURL(libcurl) into the MinGW/MSYS environment. After installed, any program can be compiled to use it with the typical <curl/curl.h> and -lcurl conventions since it's installed where GCC would expect it. I documented my process here.
When i am trying to compile a C code which uses openssl 'crypto' library functions with comand line -lcrypto with gcc 4.4.3 it gives an error
`#ubu:$ gcc -ggdb aes_m.c -Werror -Wall -I /usr/local/ssl/include/ -lcrypto -o aes
/usr/bin/ld: cannot find -lcrypto
collect2: ld returned 1 exit status`
what can be the reason for this??
I have already gone through this discussion ld cannot find an existing library but that does not help.
locate command results in
$ locate libcrypto
/home/abhi/Downloads/openssl-1.0.1b/libcrypto.a
/home/abhi/Downloads/openssl-1.0.1b/libcrypto.pc
/lib/libcrypto.so.0.9.8
/lib/i486/libcrypto.so.0.9.8
/lib/i586/libcrypto.so.0.9.8
/lib/i686/cmov/libcrypto.so.0.9.8
/usr/lib/libcrypto.so.0.9.8
/usr/lib/vmware-tools/lib32/libcrypto.so.0.9.8
/usr/lib/vmware-tools/lib32/libcrypto.so.0.9.8/libcrypto.so.0.9.8
/usr/lib/vmware-tools/lib64/libcrypto.so.0.9.8
/usr/lib/vmware-tools/lib64/libcrypto.so.0.9.8/libcrypto.so.0.9.8
/usr/local/ssl/lib/libcrypto.a
/usr/local/ssl/lib/pkgconfig/libcrypto.pc
Can someone please help on this or point out any mistake i am doing
# Daniel Roethlisberger tried using the -L flag but that resulted in these errors
gcc -ggdb aes_m.c -Werror -Wall -I /usr/local/ssl/include/ -L /usr/local/ssl/lib -lcrypto -o aes
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_globallookup':
dso_dlfcn.c:(.text+0x2d): undefined reference to `dlopen'
dso_dlfcn.c:(.text+0x43): undefined reference to `dlsym'
dso_dlfcn.c:(.text+0x4d): undefined reference to `dlclose'
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_pathbyaddr':
dso_dlfcn.c:(.text+0x8f): undefined reference to `dladdr'
dso_dlfcn.c:(.text+0xe9): undefined reference to `dlerror'
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_func':
dso_dlfcn.c:(.text+0x4b1): undefined reference to `dlsym'
dso_dlfcn.c:(.text+0x590): undefined reference to `dlerror'
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_var':
dso_dlfcn.c:(.text+0x611): undefined reference to `dlsym'
dso_dlfcn.c:(.text+0x6f0): undefined reference to `dlerror'
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_unload':
dso_dlfcn.c:(.text+0x755): undefined reference to `dlclose'
/usr/local/ssl/lib/libcrypto.a(dso_dlfcn.o): In function `dlfcn_load':
dso_dlfcn.c:(.text+0x837): undefined reference to `dlopen'
dso_dlfcn.c:(.text+0x8ae): undefined reference to `dlclose'
dso_dlfcn.c:(.text+0x8f5): undefined reference to `dlerror'
collect2: ld returned 1 exit status
Many thanks
Add -L /usr/local/ssl/lib/ into the GCC command line, before the -lcrypto. Since you are building against the OpenSSL headers under /usr/local/ssl, you also need to link against the actual library under the same prefix (even though you only appear to have a static one installed there, that may or may not be your intention; you may need to properly reinstall your OpenSSL built from source).
(edit) To fix the dlopen() and friends not being found by the linker, add -ldl into the GCC command line. -ldl tells the linker to also link against libdl.so, which is the shared library containing dlopen(), dlsym(), dlclose() etc.; these functions are used by OpenSSL internally and thus, -ldl is an indirect dependency when using -lcrypto (on Linux). Because you are linking to a static version of libcrypto, you need to explicitly link against all indirect dependencies.
If you are not familiar with linking to the proper libraries, I'd suggest you use OpenSSL as installed from your Operating System package manager; it might save you some trouble.
This might be relevant for people who tried to build their own openssl from source and then use it to compile other programs (in my case Git)
During configuration of openssl, add 'shared' option:
./config shared
This will create the required shared library libcrypto.so. You'll find more in the INSTALL file.
Also, if you run into this error during 'make'
"....can not be used when making a shared object
recompile with -fPIC
./config shared -fPIC