When GCC is Not Smart Enough to Help

Have you noticed in the later versions of gcc that you have added lots of bogus warning-errors that suck the joy out of programming? Well, even with

-Wall -Werror

sometimes it won't help:

class X {
public:
  typedef enum {
    ERR1,
    ERR2
  } IOErrorCode;
  const char* IOstrerror(IOErrorCode c); // string describing the error
};

struct S {
 // ...
 X::IOErrorCode status;
};

On another day and in another file I coded:

struct S* res = malloc(sizeof(struct S));
if(! DoSomeIO(res))
  printf("IO/Error: %s (%d)\n", \
         X::IOErrorCode(res->status), res->status);//(*)

and when I ran the program I would get a segfault at line (*) and GDB was indicating that the stack was partially smashed! Niice!

After scratching my head for half an hour it occured to me that I made a mistake: I coded

IOErrorCode(res->status) // BAAD

instead of

IOstrerror(res->status) // OK

The former is [in C++] a typecast to type IOErrorCode and will cause a crash inside printf().

The latter is a function call.

Ha! Not paying attention to my own code! And I had this sequence in five places handling I/O errors!

This is the most dangerous kind of error as one hits this code path infrequently (sometimes it only happens at a client's site thus driving the client mad).

-ulianov