Std::to_string not working

cocos2d-x C++
#1

Hi,
For some reason std::to_string doesn’t work on Android Compilation, it simply states that to_string is not member of std . I am using cocos2d 3.10
Solution is to use StringUtils::toString .

#2

or you can use:

char buffer[5];
sprintf(buffer, “%d”, someint);

#3

Related Solution

#4

Or just create a header file like this, and include it:

#ifndef Templates_h
#define Templates_h

#include <string>
#include <sstream>

using namespace std;

namespace std
{
    template < typename T > std::string to_string( const T& n )
    {
        std::ostringstream stm ;
        stm << n ;
        return stm.str() ;
    }
}

#endif  // Templates_h
#5

I love how this keeps coming up.

As I recall switching APP_STL from gnu_static to c++_static was the agreed solution, but I don’t think a date was ever planned. Not sure about compatibility issues, maybe it should wait until 4.0?

@slackmoehrle can you please find out when/if this change is going to happen?
Relevant topic here: Why gnustl_static?

#6

cocos2d and sdkbox compile and work just fine with c++_static

#7

Yes c++_static compiles fine but it isn’t the default, so new users get confused and waste time. Not sure if changing the default will cause problems for pre-existing projects, which is why I asked about waiting until 4.0

My biggest annoyance is the pre-compiled library packaged with Cocos doesn’t use c++_static. I tried compiling them myself with c++_static and gen-libs but couldn’t get it work.

#8

I am seeking assistance with this.

1 Like
#9

cpp project links c++_static is fine. However, js-binding and lua-binding have a problem.

js-binding problem

spidermonkey prebuilt binary(libjs_static.a) links libstdc++.
For supporting libc++, it must provide two prebuilt binaries that is linking libstdc++ and linking libc++, such as “Play Game Services for C++” SDK.

lua-binding problem

At c++_static compiles, link error luajit is failed because of Android NDK bug
(details https://code.google.com/p/android/issues/detail?id=73907 ).

this error is not still fixed on r10e. It must wait until releasing bugfix Android NDK version.

#10

I just use this:

std::string to_str(int t) {
    std::stringstream ss;
    ss << t;
    std::string str = ss.str();
    return str;
}

std::string to_str(float t) {
    std::stringstream ss;
    ss << t;
    std::string str = ss.str();
    return str;
}

std::string to_str(long t) {
    std::stringstream ss;
    ss << t;
    std::string str = ss.str();
    return str;
}

std::string to_str(double t) {
    std::stringstream ss;
    ss << t;
    std::string str = ss.str();
    return str;
}

int from_str_to_int(std::string t){
    const char* buffer = t.c_str();
    int i = atoi(buffer);
    return i;
}

long from_str_to_long(std::string t){
    const char* buffer = t.c_str();
    long i = atol(buffer);
    return i;
}

double from_str_to_double(std::string t){
    const char* buffer = t.c_str();
    double i = atof(buffer);
    return i;
}

float from_str_to_float(std::string t){
    const char* buffer = t.c_str();
    float i = atof(buffer);
    return i;
}
#11

@piotrros I know some people don’t like templates or won’t use them, but that 99% duplicate code is one place where it’s a no brainer I would think.

#12

I’m using code below, and it should work.

   template <typename T>
std::string to_string(T value)
{
    std::ostringstream os ;
    os << value ;
    return os.str() ;
}

method to_string will be called depend on method above.

#13

I know that! I wanted to use template, but had some issues on ms compiler if I remember correctly.