I have a piece of code in my .y file as follows
void yyerror(s) char *s; {
fputs(s, stderr);
putc('\n', stderr);
}
The function prototype declaration is in another file as follows
void yyerror (char const *s);
I tried to compile the code on both Linux and mac. On Linux, the compiler generates the following error message
error: argument ‘s’ doesn’t match prototype
void yyerror(s) char *s; {
^
On mac, the compiler generates the following warning message
warning: promoted type 'char *' of K&R function parameter is not compatible with the parameter type 'const char *' declared in a previous prototype [-Wknr-promoted-parameter]
void yyerror(s) char *s; {
^
My questions are:
Why clang only generates warning while cc generates an error.
Both compilers complain about 's' in "char *s". Why they ignore the 's' in () but consider the second 's' as the argument?
int main()
{
auto k = int();//ok
auto i = unsigned int();//gcc error
return 0;
}
The line of "auto i" leads to gcc reporint an eror:
error: expected primary-expression before 'unsigned'
While VC doesn't have problem on my code. Why is this, is this a bug of gcc or, should it use some extra parences?
Thanks.
I am compiling the following code using clang 3.4.2 ..
#include <stdio.h>
void haa(int& j){
j=1;
}
int main(){
printf("hello\n");
}
This gives the following error:
hello.c:3:13: error: expected ')'
void haa(int& j){
^
hello.c:3:9: note: to match this '('
void haa(int& j){
^
hello.c:3:13: error: parameter name omitted
void haa(int& j){
^
hello.c:4:2: error: use of undeclared identifier 'j'
j=1;
^
3 errors generated.
Compiling the same with gcc gives no errors or warnings...
Can someone explain why this is happening?
The issue is that pass by reference (with references and not pointers) is not a c but a c++ feature.
You need to compile the code with a c++ compiler such as g++ or clang++. Changing the file extension to .cpp also works, as this tells the compiler to treat it as a c++.
I've been working on a C++ project using Boost, and between compiles, I must have upgraded something in boost without meaning to or something, because now Boost dependencies won't compile:
In file included from /usr/include/boost/thread/pthread/mutex.hpp:14:0,
from /usr/include/boost/thread/mutex.hpp:16,
from /usr/include/boost/thread/pthread/thread_data.hpp:12,
from /usr/include/boost/thread/thread.hpp:17,
from /usr/include/boost/thread.hpp:13,
from /blah.h:4,
from bluh.h:3,
from bleh/main.cpp:4:
/usr/include/boost/thread/xtime.hpp:23:5: error: expected identifier before numeric constant
/usr/include/boost/thread/xtime.hpp:23:5: error: expected '}' before numeric constant
/usr/include/boost/thread/xtime.hpp:23:5: error: expected unqualified-id before numeric constant
/usr/include/boost/thread/xtime.hpp:46:14: error: expected type-specifier before 'system_time'
In file included from /usr/include/boost/thread/pthread/mutex.hpp:14:0,
from /usr/include/boost/thread/mutex.hpp:16,
from /usr/include/boost/thread/pthread/thread_data.hpp:12,
from /usr/include/boost/thread/thread.hpp:17,
from /usr/include/boost/thread.hpp:13,
from /blah,
from /bleh,(changed these names, obviously)
from /bluh /main.cpp:4:
/usr/include/boost/thread/xtime.hpp: In function 'int xtime_get(xtime*, int)':
/usr/include/boost/thread/xtime.hpp:73:40: error: 'get_system_time' was not declared in this scope
/usr/include/boost/thread/xtime.hpp:73:40: note: suggested alternative:
/usr/include/boost/thread/thread_time.hpp:19:24: note: 'boost::get_system_time'
/usr/include/boost/thread/xtime.hpp: At global scope:
/usr/include/boost/thread/xtime.hpp:88:1: error: expected declaration before '}' token
make[2]: *** [CMakeFiles/edge_based_tracker.dir/main.o] Error 1
make[1]: *** [CMakeFiles/edge_based_tracker.dir/all] Error 2
make: *** [all] Error 2
Any ideas? I tried changing TIME_UTC to TIME_UTC_ as this was recommended to me on another site, but that didn't seem to help.
EDIT: The Boost Version is Version: 1.48.0.2. I've attached xtime below:
// Copyright (C) 2001-2003
// William E. Kempf
// Copyright (C) 2007-8 Anthony Williams
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_XTIME_WEK070601_HPP
#define BOOST_XTIME_WEK070601_HPP
#include <boost/thread/detail/config.hpp>
#include <boost/cstdint.hpp>
#include <boost/thread/thread_time.hpp>
#include <boost/date_time/posix_time/conversion.hpp>
#include <boost/config/abi_prefix.hpp>
namespace boost {
enum xtime_clock_types
{
TIME_UTC=1 //LINE 23
// TIME_TAI,
// TIME_MONOTONIC,
// TIME_PROCESS,
// TIME_THREAD,
// TIME_LOCAL,
// TIME_SYNC,
// TIME_RESOLUTION
};
struct xtime
{
#if defined(BOOST_NO_INT64_T)
typedef int_fast32_t xtime_sec_t; //INT_FAST32_MIN <= sec <= INT_FAST32_MAX
#else
typedef int_fast64_t xtime_sec_t; //INT_FAST64_MIN <= sec <= INT_FAST64_MAX
#endif
typedef int_fast32_t xtime_nsec_t; //0 <= xtime.nsec < NANOSECONDS_PER_SECOND
xtime_sec_t sec;
xtime_nsec_t nsec;
operator system_time() const
{
return boost::posix_time::from_time_t(0)+
boost::posix_time::seconds(static_cast<long>(sec))+
#ifdef BOOST_DATE_TIME_HAS_NANOSECONDS
boost::posix_time::nanoseconds(nsec);
#else
boost::posix_time::microseconds((nsec+500)/1000);
#endif
}
};
inline xtime get_xtime(boost::system_time const& abs_time)
{
xtime res;
boost::posix_time::time_duration const time_since_epoch=abs_time-boost::posix_time::from_time_t(0);
res.sec=static_cast<xtime::xtime_sec_t>(time_since_epoch.total_seconds());
res.nsec=static_cast<xtime::xtime_nsec_t>(time_since_epoch.fractional_seconds()*(1000000000/time_since_epoch.ticks_per_second()));
return res;
}
inline int xtime_get(struct xtime* xtp, int clock_type)
{
if (clock_type == TIME_UTC)
{
*xtp=get_xtime(get_system_time());
return clock_type;
}
return 0;
}
inline int xtime_cmp(const xtime& xt1, const xtime& xt2)
{
if (xt1.sec == xt2.sec)
return (int)(xt1.nsec - xt2.nsec);
else
return (xt1.sec > xt2.sec) ? 1 : -1;
}
} // namespace boost
#include <boost/config/abi_suffix.hpp>
#endif //BOOST_XTIME_WEK070601_HPP
EDIT: To make it clear, the code is failing on an import of boost/thread.hpp
For those running into the same issue and struggling to find the solution here.
Derived from noodlebox' link (https://svn.boost.org/trac/boost/ticket/6940):
You can edit /usr/include/boost/thread/xtime.hpp (or whereever your xtime.hpp lies)
and change all occurrences of TIME_UTC to TIME_UTC_ - Probably around lines 23 and 71.
i.e. sed -i 's/TIME_UTC/TIME_UTC_/g' /usr/include/boost/thread/xtime.hpp
If you're getting syntax errors when using Boost, you may need to compile your code with -std=c++11.
The TIME_UTC issue you might have read about is a side effect of using c++11. TIME_UTC is now defined as a macro in c++11, so you will need to either replace all instances of TIME_UTC with TIME_UTC_, or just use a newer (1.50.0+) version of Boost where this has been fixed already.
See: https://svn.boost.org/trac/boost/ticket/6940
Since you do not show your code, we can only guess. My guess is that you define TIME_UTC macro somewhere in your code. This macro messes-up xtime.hpp header.
I am trying to compile my code in vs2005.
I am using std::map and boost::shared_ptr (v1.47.0)
My code looks something like this
struct B {
int a;
}
typedef boost::shared_ptr<B> K;
std::map<const std::string, K > mymap;
//some code
std::map<const std::string, K >::iterator it;
for (it = mymap.begin(); it < mymap.end(); it++ )
{
//do something
}
The compiler is giving an error at the for statement.
The following is the error
error C2784: 'bool boost::operator <(const boost::intrusive_ptr &,const boost::intrusive_ptr &)' : could not deduce template argument for 'const boost::intrusive_ptr &' from 'std::_Tree<_Traits>::iterator'.
Any help is appreciated.
Thank you.
You are using the wrong operator for the checking against mymap.end(). Change the loop to
for (it = mymap.begin(); it != mymap.end(); it++ )