How to convert void* to foo* to comply with C++? -


i trying compile code written in c (ndpireader.c program comes ndpi library, hosted here). i'm using qt creator , gcc compiler.

after doing research here , here, notice compiling c code c++ compiler not best idea. didn't answer of how conversion , make code c++ compatible.

when try run code in qt creator error bellow:

error: invalid conversion 'void*' 'ndpi_flow_struct*' [-fpermissive] if((newflow->ndpi_flow = malloc_wrapper(size_flow_struct)) == null) { ^

if more info needed solve problem please leave comment. i'm new c++ detailed answers links appreciated.

edit: here malloc_wrapper() function's code

static void *malloc_wrapper(unsigned long size) {   current_ndpi_memory += size;    if(current_ndpi_memory > max_ndpi_memory)     max_ndpi_memory = current_ndpi_memory;    return malloc(size); }

you're seeing error because in c++, types should have exact match.

as can see, malloc_wrapper() function returns void * , newflow->ndpi_flow of type ndpi_flow_struct*. while compiling using c++ compiler, you've add cast, like

if((newflow->ndpi_flow=(ndpi_flow_struct*)malloc_wrapper(size_flow_struct)) == null) { . . .

to force compiler in believing return value of malloc_wrapper() of type (ndpi_flow_struct*).

or better, static cast<> (keeping in mind c++ aspect), like

if(( newflow->ndpi_flow =                  static_cast<ndpi_flow_struct*>malloc_wrapper(size_flow_struct)) == null) { . . .

related reading: a detailed answer on c++ casting.


Comments

Post a Comment

Popular posts from this blog

How to group boxplot outliers in gnuplot -

i have large set of data points. try plot them boxplot, of outliers exact same value , represented on line beside each other. found how set horizontal distance between outliers in gnuplot boxplot , doesn't much, apparently not possible. is possible group outliers together, print 1 point , print number in brackets beside indicate how many points there are? think make more readable in graph. for information, have 3 boxplots 1 x value , times 6 in 1 graph. using gnuplot 5 , played around pointsize, doesn't reduce distance anymore. hope can help! edit: set terminal pdf set output 'dat.pdf' file0 = 'dat1.dat' file1 = 'dat2.dat' file2 = 'dat3.dat' set pointsize 0.2 set notitle set xlabel 'x' set ylabel 'y' header = system('head -1 '.file0); n = words(header) set xtics ('' 1) set [i=1:n] xtics add (word(header, i) i) set style data boxplot plot file0 using (1-0.25):1:(0.2) boxplot lw 2 lc rgb '#8b0000...
Read more

cakephp - simple blog with croogo -

i not problem, made simple blog in croogo, problem is not adding or modifying or delete, because arabic language ?? function add in controller `public function admin_add() { $this->set('title_for_layout', __('add part')); if (!empty($this->request->data)) { $this->part->create(); if ($this->part->save($this->request->data)) { $this->session->setflash(__('the part has been saved'), 'default', array('class' => 'success')); $this->redirect(array('action' => 'index'));//, $this->part->id)); } else { $this->session->setflash(__('the part not saved. please, try again.'), 'default', array('class' => 'error')); } } }` => model `class part extends appmodel { public $name = 'part'; var $belongst...
Read more