• Michael Butscher <mbutscher gmx.de> Jun 07 2005
• "Uwe Salomon" <post uwesalomon.de> Jun 07 2005
• Vathix <vathix dprogramming.com> Jun 07 2005
• Michael Butscher <mbutscher gmx.de> Jun 08 2005
• Chris Sauls <ibisbasenji gmail.com> Jun 07 2005
• Michael Butscher <mbutscher gmx.de> Jun 09 2005

Michael Butscher <mbutscher gmx.de> writes:

Hi,

the problem I want to solve is that some functions should be exported to a DLL 
(or not) based on a version identifier. This probably could be done also by 
editing the .def file but would be rather inconvenient.


Example:

----------

version(DLL_C)   // If we want a DLL interface for C
{
  export:
  extern(C):
}

int forC_aaa()
{...}

int forC_bbb()
{...}

noexport:  // Stop exporting
extern(D):  // Stop C linkage



int helper()  // Never exported
{...}



version(DLL_D)   // If we want a DLL interface for D
{
  export:
}

int aaa()
{...}

int bbb()
{...}

noexport:  // Stop exporting

----------


It would be nice also if it could be written this way:

version(DLL_D) {export} int aaa()

But maybe hard to implement.



Michael

"Uwe Salomon" <post uwesalomon.de> writes:

 version(DLL_C)   // If we want a DLL interface for C
 {
   export:
   extern(C):
 }


AFAIK, this will not work as you expect! version() is not the same as  
#ifdef and friends, where you "include" something. The scope of export:  
and extern: ends at the closing brace! Anything after version() will have  
the normal D linkage.

Ciao
uwe

Vathix <vathix dprogramming.com> writes:

On Tue, 07 Jun 2005 15:30:14 -0400, Uwe Salomon <post uwesalomon.de> wrote:

 version(DLL_C)   // If we want a DLL interface for C
 {
   export:
   extern(C):
 }


 AFAIK, this will not work as you expect! version() is not the same as  
 #ifdef and friends, where you "include" something. The scope of export:  
 and extern: ends at the closing brace! Anything after version() will  
 have the normal D linkage.

 Ciao
 uwe


Sometimes { } doesn't introduce a new scope, depending on the statement.  
In this case I don't think it does and so it should work how he is using  
it.

Michael Butscher <mbutscher gmx.de> writes:

Uwe Salomon wrote:
 version(DLL_C)   // If we want a DLL interface for C
 {
   export:
   extern(C):
 }


 AFAIK, this will not work as you expect! version() is not the same as  
 #ifdef and friends, where you "include" something. The scope of export:  
 and extern: ends at the closing brace! Anything after version() will have  
 the normal D linkage.
 
 Ciao
 uwe



I tried it and it works (tested with DMD 0.124).


Michael

Chris Sauls <ibisbasenji gmail.com> writes:

Since 'export' is a protection attribute, you can end any 'export:' 
attribute-statement by introducing a new protection attribute, such as 
'public'.  In other words:

# version(DLL_C) {
#   export:
#   extern(C):
# }
#
# int forC_aaa() { ... }
# int forC_bbb() { ... }
#
# public:
# extern(D): // default is D, but it may be good to be explicit here
#
# int helper() { ... }
#
# version(DLL_D) {
#   export:
# }
#
# int aaa() { ... }
# int bbb() { ... }
#
# public:


 It would be nice also if it could be written this way:
 
 version(DLL_D) {export} int aaa()
 
 But maybe hard to implement.


Maybe the 'alias' statement could be given a new case for attribute 
symbols...  so you could do something like:

# version (DLL_D) { alias export a_AttrProtection; }
# else            { alias public a_AttrProtection; }
#
# a_AttrProtection int aaa() { ... }

-- Chris Sauls

Michael Butscher <mbutscher gmx.de> writes:

Chris Sauls wrote:
 Since 'export' is a protection attribute, you can end any 'export:' 
 attribute-statement by introducing a new protection attribute, such as 
 'public'.  In other words:
 
 # version(DLL_C) {
 #   export:
 #   extern(C):
 # }
 #
 # int forC_aaa() { ... }
 # int forC_bbb() { ... }
 #
 # public:
 # extern(D): // default is D, but it may be good to be explicit here
 #
 # int helper() { ... }
 #
 # version(DLL_D) {
 #   export:
 # }
 #
 # int aaa() { ... }
 # int bbb() { ... }
 #
 # public:



Thank you!


Michael