c - using #defines and passing functions to them -

-

gcc 4.4.2 c89

I re-engineer some code in c89. However, I am completely confused with the code which defines the following #. So I have created a small application, maybe I understand how it is working.

What I can collect MODULE_API will pass the function name and the macro will call MODULE_SOURCE_API and open the name and function. So I created a simple function called print_name and ran the code. I have received the following error message: 

  The underlying declaration of the function 'print_name' is the undefined reference to 'print_name'

What would be the main reason for doing this? 

  #include & lt; Stdio.h & gt; #define MODULE_SOURCE_API (name, func) name ## _ ## func #define MODULE_API (func) MODULE_SOURCE_API (mod_print, func) ZERO MODULE_API (print_name) (CONSTORE FOUR CONST * name); Int main (zero) {printf ("=== Start the program === \ n"); Print_name ("Blogs"); Printf ("== Program End === \ n"); Return 0; } Zero MODULE_API (print_name) (const four console * name) {printf ("my name is [% s] \ n", name); }

Many thanks for any advice,

Edit ==== I have made a correction which I should call

< Pre> MODULE_API (print_name) ("blogs");

But how do I get involved, how can I print it? And what is the reason for doing this?

Many thanks, 

  #define MODULE_SOURCE_API (name, function) Name ##_## function #define MODULE_API (func) MODULE_SOURCE_API (mod_print, func) Zero MODULE_API (print_name) (Const four contact * names);   
 This will produce the  mod_print_print_name  function instead of  print_name  
 
 
 
 
 You can see it on the  GCC  
  gcc-e ak.c  
 
  / * ...... * / Zero mod_print_print_name (const four contact * names); Int main (zero) {printf ("=== Start the program === \ n"); Print_name ("Blogs"); Printf ("== Program End === \ n"); Return 0; } Zero mod_print_print_name (const four const * name) {printf ("my name is [% s] \ n", name); }

Comments

Post a Comment

Popular posts from this blog

oracle - The fastest way to check if some records in a database table? -

-
I have a big table to work with. I have to see that there are some records whose parent_id is equal to my passing value. Currently I do this by implementing "my_table using select count (*) where parent_id =: id"; If the result> 0, it means that they exist. Because this is a very large table, and I do not care what the actual number of records present, I just want to know if it exists, so I think count (*) Bit is disabled. How do I apply this requirement most quickly? I'm using Oracle 10. # Tips for Hibernation & amp; Tricks It suggests writing in such a way: Integer number = (integer) session .createQuery ("Select Count (*) to ...."). UniqueResult (); I do not know what is the magic of the unique rule? Why does it fast? To compare, select "1 from mytable where parent_id = passId and rowrum", which is more efficient? If you are not interested in the number of records, then there is an EXISTS query one: Select 'y'
Read more

php - multilevel menu with multilevel array -

-
Just ask someone to solve this problem? I want to create a multilevel menu I can not find the right solution generated with multilevel array, it always gets an array_push error My study came from the original idea But still my Can not match the need. This is my MySQL [code] ----- --------------------- --------------- | ID | PARENT_ID | Name | Link | Seq | 1 | 0 | Dashboad | Dashboard / | 1 | 2 | 0 | Menu 1 | Menu 1 / | 2 | 3 | 0 | Menu 2 | Menu 2 / | 3 | 4 | 0 | Menu 3 | Menu 3 / | 4 | 5 | 2 | Joint Add / | 1 | 6 | 3 | Joint Add / | 1 | 7 | 2 | Edit | Edit / | 2 | 8 | 4 | Joint Add / | 1 ------------------------------------------ [/ Code] I want to do something like this in my array array ('dashboard' = & gt; array ('id' = & gt; '' 'Dame' = & gt; 'Dashboard', 'Title' = & gt; 'Dashboard', 'MatchMin' = & gt; Base_URL (). 'Dashboard /', 'Active' => = & Gt; NULL), &
Read more

jQuery UI: Datepicker month format -

-
I am trying to change the format of the month that shows in the popup (not in the date that the picker actually I do not have any choice anywhere to do this, do I like to use a sub-string () or something else? What I normally display is Trying to change: Class = "ui-datepicker-title"> January & lt; / span & gt; ... & lt; / div & gt; Div>
Read more