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digitalmars.D.learn - Passing to c++ std::string and vector

reply NewUser <NewUser newUser.com> writes:
Hi,

How do I pass a d string to a c++ std::string?

NewUser
Apr 29 2018
next sibling parent Uknown <sireeshkodali1 gmail.com> writes:
On Monday, 30 April 2018 at 01:07:35 UTC, NewUser wrote:

 Hi,

 How do I pass a d string to a c++ std::string?

 NewUser


There is no trivial way to do this as far as I'm aware, mostly 
due to C++ mangling issues in DMD. You can try calypso [0] or dpp 
[1], which might work. You can also see this PR[2]

[0]: https://wiki.dlang.org/Calypso
[1]: 
https://forum.dlang.org/post/kbcdppawjtcdkdtdzwwp forum.dlang.org
[2]: https://github.com/dlang/druntime/pull/1316
Apr 30 2018
prev sibling next sibling parent reply Jonathan M Davis <newsgroup.d jmdavisprog.com> writes:
On Monday, April 30, 2018 01:07:35 NewUser via Digitalmars-d-learn wrote:

 Hi,

 How do I pass a d string to a c++ std::string?


The most straightforward way would be to create a C or C++ function which
accepts const char* and size_t and then creates the std::string, in which
case you pass it arr.ptr (or &arr[0]) and arr.length from D (and you could
create a D helper function that takes a dynamic array to then call the C/C++
function if you don't want to use the array properties directly every time).

Essentially, you'll probably end up creating wrapper functions for any C++
functions that you want to call that take std::string, since there is not
currently a straightforward way to construct a std::string from D (there's
Calypso, but using it means that you're tied to ldc). Solutions are likely
forthcoming, but there's nothing production-ready at this point. Do
interacts reasonably well when it's operatoring on pointers to C++ classes,
but as soon as it has to deal with construction or destruction, things get
more complicated (which means that C++ classes on the stack definitely get
more complicated). You can still get things to work, but it's frequently not
straightforward in the way that calling C functions is.

- Jonathan M Davis
Apr 30 2018
parent NewUser <NewUser newuser.com> writes:
On Monday, 30 April 2018 at 10:48:40 UTC, Jonathan M Davis wrote:

 On Monday, April 30, 2018 01:07:35 NewUser via 
 Digitalmars-d-learn wrote:

 Hi,

 How do I pass a d string to a c++ std::string?


 The most straightforward way would be to create a C or C++ 
 function which accepts const char* and size_t and then creates 
 the std::string, in which case you pass it arr.ptr (or &arr[0]) 
 and arr.length from D (and you could create a D helper function 
 that takes a dynamic array to then call the C/C++ function if 
 you don't want to use the array properties directly every time).

 Essentially, you'll probably end up creating wrapper functions 
 for any C++ functions that you want to call that take 
 std::string, since there is not currently a straightforward way 
 to construct a std::string from D (there's Calypso, but using 
 it means that you're tied to ldc). Solutions are likely 
 forthcoming, but there's nothing production-ready at this 
 point. Do interacts reasonably well when it's operatoring on 
 pointers to C++ classes, but as soon as it has to deal with 
 construction or destruction, things get more complicated (which 
 means that C++ classes on the stack definitely get more 
 complicated). You can still get things to work, but it's 
 frequently not straightforward in the way that calling C 
 functions is.

 - Jonathan M Davis


Thanks.
Apr 30 2018
prev sibling parent Seb <seb wilzba.ch> writes:
On Monday, 30 April 2018 at 01:07:35 UTC, NewUser wrote:

 Hi,

 How do I pass a d string to a c++ std::string?

 NewUser


There's https://github.com/dlang/druntime/pull/1316 (an attempt 
at making C++ standard library)
Apr 30 2018