OpenEuphoria

calling dlopen

• Posted by SDPringle Feb 13, 2014
• 1468 views

I must have some tiny bug in my code in this tiny program. Would anyone like to help?

I am using open_dll to call the C routine dlopen. I want to experiment with trying various flags in dlopen's second parameter. I wrote this new routine, dl_open_library, to do the same as open_dll but it doesn't work. I guess I am missing something obvious somewhere. Right now, I expect dl_open_library to return some non-zero value as open_dll does. This program should simply exit and print nothing to the screen.

include std/filesys.e  
include std/dll.e  
include std/machine.e  
include std/sequence.e 
include std/error.e 
include std/io.e 
 
constant KEYBOARD = 0, SCREEN = 1, ERROR = 2 
 
 
type enum boolean  
	TRUE = 1, FALSE = 0  
end type  
 
ifdef LINUX and not BITS64 then 
    -- these could be wrong on 64 bit Linux. I don't know. 
    -- from /usr/include/bits/dlfcn.h 
    constant RTLD_LAZY  = 1 
    constant RTLD_LOCAL = 0 
    constant RTLD_NOLOAD = 8, 
             RTLD_GLOBAL = #100 
end ifdef 
constant libdl = open_dll("libdl.so")   
constant dlopen_sym = define_c_func(libdl, "dlopen", {C_POINTER, C_INT}, C_POINTER) 
constant dlsym_sym  = define_c_func(libdl, "dlsym", {C_POINTER, C_POINTER}, C_POINTER) 
constant dlerror_sym = define_c_func(libdl, "dlerror", {}, C_POINTER) 
 
if libdl = 0 or dlopen_sym = -1 then 
   puts(ERROR, "Cannot get dlopen from self.\n") 
   abort(1) 
end if  
 
-- return 0 on error; positive value on success 
function dl_open_library(sequence name) 
    return c_func(dlopen_sym, {allocate_string(name, TRUE), or_bits(RTLD_LAZY, RTLD_GLOBAL)}) 
end function 
 
-- return -1 on error; non-negative on success 
function dl_get_symbol(atom handle, sequence name) 
    atom e = c_func(dlerror_sym, {}) 
    atom ret = c_func(dlsym_sym, {handle, allocate_string(name, TRUE)}) 
    e = c_func(dlerror_sym,{}) 
    if e != 0 then 
        return -1 
    end if 
    return ret 
end function 
 
if dl_open_library("/lib/libdl.so") = 0 then 
    puts(ERROR, "dl_open_library can't open what open_dll can.\n") 
    atom error_value = c_func(dlerror_sym,{}) 
    if error_value then 
        puts(ERROR, peek_string(error_value) & 10) 
    end if 
    abort(1) 
end if