g++ expected unqualified-id before ‘(’ token

I'm getting this error when using stl_vector.h. I'm on Linux using g++ to compile.

{
  if (max_size() - size() < __n)
    __throw_length_error(__N(__s));

  const size_type __len = size() + std::max(size(), __n); //THE ERROR IS ON THIS LINE!
  return (__len < size() || __len > max_size()) ? max_size() : __len;
}

usr/include/c++/4.5/bits/stl_vector.h:1143:40: error: expected unqualified-id before ‘(’ token

I'm not sure why I'm getting this error, I have searched a lot and found some "similar" problems but I can't solve mine.

EDIT: so here's the error log:

In file included from /usr/include/c++/4.5/vector:65:0,
             from ../../RL_Toolbox/include/caction.h:34,
             from ../../RL_Toolbox/include/cagent.h:35,
             from shortestpathQLearning.cpp:42:
/usr/include/c++/4.5/bits/stl_vector.h:1143:40: error: expected unqualified-id before ‘(’ token

You can see in the previous error log that "vector" gets called by the header "caction.h" like this:

//THESE ARE THE INCLUDES IN "caction.h"
#ifndef CACTION_H
#define CACTION_H
#include <stdio.h> 
#include <vector> //HERE IT CALLS <vector>
#include <list>
#include <map>
#include "cbaseobjects.h"

then Vector calls bits/stl_vector.h like this:

#ifndef _GLIBCXX_VECTOR
#define _GLIBCXX_VECTOR 1

#pragma GCC system_header

#include <bits/stl_algobase.h>
#include <bits/allocator.h>
#include <bits/stl_construct.h>
#inc开发者_如何学运维lude <bits/stl_uninitialized.h>
#include <bits/stl_vector.h>//HERE IT CALLS stl_vector.h
#include <bits/stl_bvector.h> //Im actually getting the exact same error from  stl_vector.h on this header

just the last 2 headers from vector (stl_vector and stl_bvector) give me the exact same error, the rest are ok. Any ideas?

Thanks in advance for your help.

---

This may be caused by the preprocessor damaging your code, probably because you have macro max defined. This can happen with the C library, because generally the C standard allows C standard library functions to be actually macros (although I've only seen such a mishap on MSVC).

To check, you can

• preprocess the source with gcc -E and search the output for the corresponding code. Check if it is undamaged.
• add an #undef max line before #include <vector> and see if it helps.

---

user977480, given that you said "I'm getting this error when using stl_vector.h", I assume that means your code is using something like #include <bits/stl_vector.h> or #include <c++/4.5/bits/stl_vector.h>.

This #include statement is the cause of your problem. You need to use #include <vector> instead. stl_vector.h is an implementation detail and it does not work by itself. The vector header file includes bits/stl_vector.h after it has included some other implementation detail files, including the one that defines std::max.

---

Never use identifiers starting with either a double underscore, or an underscore followed by an uppercase letter, unless they're provided by the implementation.

The compiler and/or standard library are permitted to use __N, __s, __len, and so forth, in any way they like.

It's not obvious that that's your problem, but see what happens if you change all those identifiers.

EDIT: I was wrong, the code you posted is part of the implementation, so its use of reserved identifiers is perfectly appropriate.

/usr/include/c++/4.5/bits/stl_vector.h on my system contains the same code. Most likely something in your own code is causing the error. For example, if I do

#include <bits/stl_vector.h>

I get 156 errors. The correct way is

#include <vector>

but if you #define certain macros before the #include <vector> it might cause the problem you're seeing.

Show us your code, preferably narrowed down to the smallest source file that exhibits the error.