g++ version 7.5.0 and library <memory_resource>

g++ version 7.5.0 and library <memory_resource>

[hbusch]

Hi,
I am using g++ version 7.5.0 on Linux Mint 19 Tara:

g++ (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0

When I try to compile a source file which uses the Standard library  
header <memory_resource> I get the following error:

main.cpp:7:10: fatal error: memory_resource: No such file or directory

As to my knowledge g++ version 7.5.0 supports C++17 and library  
<memory_resource> is included since C++17. At least, this page tells  
me that it has to be there:

https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/api/a01004_source.html

Even adding -std=gnu++17 throws the same error.

Can anybody please shed some light on this ?

Thanks
Regards
Harald

Re: g++ version 7.5.0 and library <memory_resource>

[Marc Glisse]

On Sun, 7 Jun 2020, hbusch@bnv-bamberg.de wrote:

> Hi,
> I am using g++ version 7.5.0 on Linux Mint 19 Tara:
>
> g++ (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
>
> When I try to compile a source file which uses the Standard library header 
> <memory_resource> I get the following error:
>
> main.cpp:7:10: fatal error: memory_resource: No such file or directory
>
> As to my knowledge g++ version 7.5.0 supports C++17 and library 
> <memory_resource> is included since C++17. At least, this page tells me that 
> it has to be there:
>
> https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/api/a01004_source.html
>
> Even adding -std=gnu++17 throws the same error.
>
> Can anybody please shed some light on this ?

Try <experimental/memory_resource>

-- 
Marc Glisse

Re: g++ version 7.5.0 and library <memory_resource>

[Jonathan Wakely]

On Sun, 7 Jun 2020 at 20:12, <hbusch@bnv-bamberg.de> wrote:
>
> Hi,
> I am using g++ version 7.5.0 on Linux Mint 19 Tara:
>
> g++ (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
>
> When I try to compile a source file which uses the Standard library
> header <memory_resource> I get the following error:
>
> main.cpp:7:10: fatal error: memory_resource: No such file or directory
>
> As to my knowledge g++ version 7.5.0 supports C++17 and library
> <memory_resource> is included since C++17. At least, this page tells
> me that it has to be there:
>
> https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/api/a01004_source.html

No it doesn't, it tells you a different header is part of libstdc++ in
the 7.5.0 release.

As https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/manual/manual/status.html#status.iso.2017
says, the <memory_resource> header is not supported in 7.5.0.

Re: g++ version 7.5.0 and library <memory_resource>

[hbusch]

Thanks a lot Jonathan for your quick help.
You are right, 7.5.0 does not include memory_resource.
Best regards
Harald

Quoting Jonathan Wakely <jwakely.gcc@gmail.com>:

> On Sun, 7 Jun 2020 at 20:12, <hbusch@bnv-bamberg.de> wrote:
>>
>> Hi,
>> I am using g++ version 7.5.0 on Linux Mint 19 Tara:
>>
>> g++ (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
>>
>> When I try to compile a source file which uses the Standard library
>> header <memory_resource> I get the following error:
>>
>> main.cpp:7:10: fatal error: memory_resource: No such file or directory
>>
>> As to my knowledge g++ version 7.5.0 supports C++17 and library
>> <memory_resource> is included since C++17. At least, this page tells
>> me that it has to be there:
>>
>> https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/api/a01004_source.html
>
> No it doesn't, it tells you a different header is part of libstdc++ in
> the 7.5.0 release.
>
> As  
> https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/manual/manual/status.html#status.iso.2017
> says, the <memory_resource> header is not supported in 7.5.0.

Re: g++ version 7.5.0 and library <memory_resource>

[hbusch]

Thanks a lot Marc for your quick help.
Even <experimental/memory_resource> did not help.

Here ...

https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/manual/manual/status.html#status.iso.2017

... I see that 7.5.0 does not include memory_resource.

Best regards
Harald

Quoting Marc Glisse <marc.glisse@inria.fr>:

> On Sun, 7 Jun 2020, hbusch@bnv-bamberg.de wrote:
>
>> Hi,
>> I am using g++ version 7.5.0 on Linux Mint 19 Tara:
>>
>> g++ (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
>>
>> When I try to compile a source file which uses the Standard library  
>> header <memory_resource> I get the following error:
>>
>> main.cpp:7:10: fatal error: memory_resource: No such file or directory
>>
>> As to my knowledge g++ version 7.5.0 supports C++17 and library  
>> <memory_resource> is included since C++17. At least, this page  
>> tells me that it has to be there:
>>
>> https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/api/a01004_source.html
>>
>> Even adding -std=gnu++17 throws the same error.
>>
>> Can anybody please shed some light on this ?
>
> Try <experimental/memory_resource>
>
> -- 
> Marc Glisse

Re: g++ version 7.5.0 and library <memory_resource>

[Jonathan Wakely]

On Mon, 8 Jun 2020 at 05:43, <hbusch@bnv-bamberg.de> wrote:
>
> Thanks a lot Marc for your quick help.
> Even <experimental/memory_resource> did not help.
>
> Here ...
>
> https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/manual/manual/status.html#status.iso.2017
>
> ... I see that 7.5.0 does not include memory_resource.

But <experimental/memory_resource> and <memory_resource> are two
different headers.

GCC 7.5.0 *does* provide <experimental/memory_resource>, as documented
in Table 1.4 at
https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/manual/manual/status.html#status.iso.2014
where it shows that the "Polymorphic memory resources" component of
the Library Fundamental Techncial Specification is partially
supported.

Re: g++ version 7.5.0 and library <memory_resource>

[hbusch]

You are right Jonathan, at least I do not get an error from the  
compiler complaining about <memory_resource> when I use  
<experimental/memory_resource>.

However, the next hurdle for the compiler is the following statement:

std::pmr::monotonic_buffer_resource ...

So at least this seems not be be included.

Thanks for your kind help here.

Best regards
Harald


Thanks a lot Jonatahan f

Quoting Jonathan Wakely <jwakely.gcc@gmail.com>:

> On Mon, 8 Jun 2020 at 05:43, <hbusch@bnv-bamberg.de> wrote:
>>
>> Thanks a lot Marc for your quick help.
>> Even <experimental/memory_resource> did not help.
>>
>> Here ...
>>
>> https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/manual/manual/status.html#status.iso.2017
>>
>> ... I see that 7.5.0 does not include memory_resource.
>
> But <experimental/memory_resource> and <memory_resource> are two
> different headers.
>
> GCC 7.5.0 *does* provide <experimental/memory_resource>, as documented
> in Table 1.4 at
> https://gcc.gnu.org/onlinedocs/gcc-7.5.0/libstdc++/manual/manual/status.html#status.iso.2014
> where it shows that the "Polymorphic memory resources" component of
> the Library Fundamental Techncial Specification is partially
> supported.

Re: g++ version 7.5.0 and library <memory_resource>

[Jonathan Wakely]

On Mon, 8 Jun 2020 at 12:44, <hbusch@bnv-bamberg.de> wrote:
>
> You are right Jonathan, at least I do not get an error from the
> compiler complaining about <memory_resource> when I use
> <experimental/memory_resource>.
>
> However, the next hurdle for the compiler is the following statement:
>
> std::pmr::monotonic_buffer_resource ...
>
> So at least this seems not be be included.

It is included.

<experimental/memory_resource> is a different header from
<memory_resource>, and it provides different types and functions.

The contents of <experimental/memory_resource> as in namespace
std::experimental.

See https://en.cppreference.com/w/cpp/header/experimental/memory_resource

Maybe you should just update your compiler so you can use C++17.