Multiple errors from C assert macro -


i have assert macro that's defined as:

#define likely(cond) (__builtin_expect((cond), 1)) #define unlikely(cond) (__builtin_expect(!!(cond), 0))  static void assert_fail(const char *__assertion, const char *__file,                            unsigned int __line, const char *__function) {     fprintf(stderr, "\nassert failed %s:%d %s()\n%s\n", __file, __line, __function, __assertion);      void *array[50];     size_t size = backtrace(array, 50);     // fill out array of pointers stack entries     backtrace_symbols_fd(&array[1], size, stderr_fileno);     exit(1); }  #define assert(expr) ( likely(expr) ? (void) (0) : \                        assert_fail(#expr, __file__, __line__, __func__ ))

which works fine, except when make simple error inside assert condition, eg wrong variable name:

assert(size > 0);

it prints sensible error, 5 notes (including repeats) makes harder read. there sane way address make easier read? core issue seems use of macros, can't see how avoid here, given use of __file__, __line__, etc.

disabling "note: each undeclared identifier reported once each function" cut in half if possible (though cannot find way that)

abc.c: in function 'init': abc.c:53:12: error: 'size' undeclared (first use in function)      assert(size > 0);             ^ include/assert.h:21:41: note: in definition of macro 'likely'  #define likely(cond) (__builtin_expect((cond), 1))                                          ^ abc.c:53:5: note: in expansion of macro 'assert'      assert(size > 0);      ^ abc.c:53:12: note: each undeclared identifier reported once each function appears in      assert(size > 0);             ^ include/assert.h:21:41: note: in definition of macro 'likely'  #define likely(cond) (__builtin_expect((cond), 1))                                          ^ abc.c:53:5: note: in expansion of macro 'assert'      assert(size > 0);      ^

as general rule, when dealing compiler errors, address first error find recompile. way don't waste time chasing down cascading errors.

in particular case, you'll notice have "error" line followed several "note" lines. whenever see "note" message, it's giving additional information on recent "error" or "warning message". shouldn't suppress messages these (and don't believe can), can give valuable information on true source of error.

here's example of these "note" messages useful:

#include <stdio.h>  void f1(double x);  int main() {     f1(3);     return 0; }   void f1(int x) {     printf("x=%d\n", x); }

in code declaration of f1 doesn't match definition. compiler generate following message:

x1.c:12:6: error: conflicting types ‘f1’  void f1(int x)       ^ x1.c:3:6: note: previous declaration of ‘f1’ here  void f1(double x);

the "error" message tells definition @ line 12 doesn't match declaration, doesn't declaration conflicts with. appears in "note" message follows. in large project, might have trouble finding conflict without "note" message.


Comments

Post a Comment

Popular posts from this blog

android - InAppBilling registering BroadcastReceiver in AndroidManifest -

i'm implementing inapp billing in android app. works well, however, i'm trying decouple broadcast receiver activity manifest. suggestion in android's trivialdrive sample: // important: dynamically register broadcast messages updated purchases. // register receiver here instead of <receiver> in manifest // because call getpurchases() @ startup, therefore can ignore // broadcasts sent while app isn't running. // note: registering listener in activity bad idea, done here // because sample. regardless, receiver must registered after // iabhelper setup, before first call getpurchases(). currently there's class extends broadcastreceiver : public class iabbroadcastreceiver extends broadcastreceiver { /** * intent action receiver should filter for. */ public static final string action = "com.android.vending.billing.purchases_updated"; private final iabbroadcastlistener mlistener; public iabbroadcastreceiver(iabbroadcastlistener listener) { m...
Read more

python Tkinter Capturing keyboard events save as one single string -

is possible store keyboard events 1 string? code below stores 1 char , prints it. card reader or bar code reader, contains collection of character/ string not 1 character @ time. goal save char pressed text variable. from tkinter import * root = tk() def key(event): text= event.char text+= event.char print ("pressed", text) def callback(event): frame.focus_set() print ("clicked at", event.x, event.y) frame = frame(root, width=100, height=100) frame.bind("<key>", key) frame.bind("<button-1>", callback) frame.pack() root.mainloop() currently, creating text variable , everytime key() function gets called, , text stores last character typed. you can define text module level variable , , use module level text inside key function - text = '' def key(event): global text text+= event.char print("pressed", text)
Read more

sql server - Why does Linq-to-SQL add unnecessary COUNT()? -

here tables: create table customer ( cid int primary key, name varchar(32) ) create table ord ( oid int primary key, cid int foreign key references customer, address varchar(20) ) here's linq-to-sql statement: var aaa = c in db.customer select new { c, o = c.ord.tolist() }; and here's inexplicable query generated linq-to-sql: select [t0].[cid] [cid], [t0].[name] [name], [t1].[oid] [oid], [t1].[cid] [cid2], [t1].[address] [address], (select count(*) [dbo].[ord] [t2] [t2].[cid] = [t0].[cid]) [value] [dbo].[customer] [t0] left outer join [dbo].[ord] [t1] on [t1].[cid] = [t0].[cid] order [t0].[cid], [t1].[oid] i want understand how rid of count(*) part. it's entirely uncalled for! linq needs count(*) in order determine number of entries returned o = c.ord.tolist() .
Read more