expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘{’ token when I have using ::va_list;

Question

I am including cstdarg and get the following error:

expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘attribute’ before ‘{’ token"

The error occurs on the following line:

  using ::va_list;

Here is the content of cstdarg:

#pragma GCC system_header

#include </usr/include/c++/4.6.3/x86_64-linux-gnu/bits/c++config.h>

#include <stdarg.h>

#ifndef _GLIBCXX_CSTDARG

#define _GLIBCXX_CSTDARG 1

// Adhere to section 17.4.1.2 clause 5 of ISO 14882:1998

#ifndef va_end
#define va_end(ap) va_end (ap)
#endif

namespace std

{

  using ::va_list;     I get the error here!

} // namespace std

#endif

and va_list was called in this file :

#include <fcntl.h>
#include <unistd.h>
#include </usr/include/c++/4.6.3/tr1/stdarg.h>


#include <stdlib.h>
#include <sys/ioctl.h>
#include <errno.h>

#include <sys/types.h>
#include <sys/stat.h>
#include </usr/include/x86_64-linux-gnu/bits/errno.h>


#include "string.h"

#include "libnitro.h"
#include "nitro.h"

#define KVM_NODE "/dev/kvm"

int kvm_fd;
int kvm_vmfd;
struct nitro_vcpus vcpus;

 int kvm_ioctl(int type, ...)
{  
int ret;
void *arg;
va_list ap;

va_start(ap, type);
arg = va_arg(ap, void *);
va_end(ap);

ret = ioctl(kvm_fd, type, arg);
if (ret == -1)
    ret = -errno;

return ret;
}

  int kvm_vm_ioctl(int type, ...)
 {
 int ret;
 void *arg;
 va_list ap;

va_start(ap, type);
arg = va_arg(ap, void *);
va_end(ap);

ret = ioctl(kvm_vmfd, type, arg);
if (ret == -1)
    ret = -errno;

return ret;
 }

 int kvm_vcpu_ioctl(int vcpu_fd,int type, ...){
 int ret;`
 `  void *arg;`
 `  va_list ap;`

  va_start(ap, type);
arg = va_arg(ap, void *);
va_end(ap);

ret = ioctl(vcpu_fd, type, arg);
if (ret == -1)
    ret = -errno;

return ret;
}




int kvm_ioctl(int type, ...)
{

  int ret;

  void *arg;

  va_list ap;

  va_start(ap, type);
  arg = va_arg(ap, void *);
  va_end(ap);

  ret = ioctl(kvm_fd, type, arg);
  if (ret == -1)
    ret = -errno;

  return ret;
}

Answer 1

You should compile your c++ code with g++ not gcc.

Additionally, most users (and programs) expect that files that end in .c, (like libnitro.c) use the C language, not the C++ language. For c++ source code, you should name your file libnitro.cpp or libnitro.cc.