Errors compiling minimal example: "undefined reference to pthread_create" and "undefined reference to `dlopen'" (and my fixes)

[vindarel]

Hi,

Compiling webui worked instantly, but compiling the minimal example gave me these errors:

Build C Example (gcc release static)...
/usr/bin/ld: home/vince/lisp-projects/webui/examples/C/minimal//../../..//dist/libwebui-2-static.a(webui.o): in function `_webui_show_window':
webui.c:(.text+0x9c03): undefined reference to `pthread_create'
/usr/bin/ld: webui.c:(.text+0x9c0f): undefined reference to `pthread_detach'
/usr/bin/ld: webui.c:(.text+0x9daf): undefined reference to `pthread_create'
/usr/bin/ld: webui.c:(.text+0x9dbb): undefined reference to `pthread_detach'

[…]

/usr/bin/ld: /home/vince/lisp-projects/webui/examples/C/minimal//../../..//dist/libwebui-2-static.a(webui.o): in function `_webui_wv_show':
webui.c:(.text+0xce4e): undefined reference to `dlopen'
/usr/bin/ld: webui.c:(.text+0xcec6): undefined reference to `dlopen'
/usr/bin/ld: webui.c:(.text+0xcf1e): undefined reference to `dlsym'

I found a combinaison of characters in the Makefile that makes the compilation succeed and the example run:

# in examples/minimal/GNUMakefile
# BUILD FLAGS
# STATIC_BUILD_FLAGS = main.c -I"$(INCLUDE_DIR)" -L"$(LIB_DIR)"
STATIC_BUILD_FLAGS = main.c  -Wl,--no-as-needed -ldl  -I"$(INCLUDE_DIR)" -L"$(LIB_DIR)"
# DYN_BUILD_FLAGS = main.c -I"$(INCLUDE_DIR)" -L"$(LIB_DIR)"
DYN_BUILD_FLAGS = main.c  -Wl,--no-as-needed -ldl  -I"$(INCLUDE_DIR)" -L"$(LIB_DIR)"

[…]

else
	# STATIC_BUILD_FLAGS += -lpthread -lm -l$(WEBUI_LIB_NAME)-static
	STATIC_BUILD_FLAGS +=  -lm -l$(WEBUI_LIB_NAME)-static -lpthread
	# DYN_BUILD_FLAGS += -lpthread -lm
	DYN_BUILD_FLAGS += -lm -lpthread

-lpthread is moved last and I added -Wl,--no-as-needed -ldl (source: first SO answers).

minimal example: ./main runs but takes 100% CPU, ./main-dyn segfaults, both binaries of the text editor run.

---

I am on an oldish system:

Mint 20 LTS (Ubuntu Focal), x64
gcc 9.4.0

---

kuddos for the work.

[ttytm]

This is on main/nightly right?

Likely a dup of #379

[vindarel]

indeed, nightly branch, commit from May 28th a54d906 main origin/main nightly Fix GC WebView2.

[hassandraga]

Fixed. Thank you for the report.

[vindarel]

I pulled master ("4466bcf main origin/main Update webui_get_best_browser description") and I was having the same error messages when compiling the minimal example, but now I only need to add -Wl,--no-as-needed -ldl:

-STATIC_BUILD_FLAGS = main.c -I"$(INCLUDE_DIR)" -L"$(LIB_DIR)"
-DYN_BUILD_FLAGS = main.c -I"$(INCLUDE_DIR)" -L"$(LIB_DIR)"
+STATIC_BUILD_FLAGS = main.c  -Wl,--no-as-needed -ldl  -I"$(INCLUDE_DIR)" -L"$(LIB_DIR)"
+DYN_BUILD_FLAGS = main.c  -Wl,--no-as-needed -ldl  -I"$(INCLUDE_DIR)" -L"$(LIB_DIR)"

[hassandraga]

I see, after we added WebView dynamic load feature to WebUI 2.5.0 Beta 1, libdl (-ldl) should be added to all GNU's makefiles as well.