Question

I’m creating a web service using gSoap, in the header file I have few method definitions that their return type is enum value.
When I’m executing the soapcpp2.exe tool and passing with the header file I’m getting this error:

sample.h(20): syntax error
sample.h(21): Syntax error: input before ; skipped

In addition, if I have more than one method with the enum as the return value I’m getting this warning:

**WARNING**: Duplicate declaration of 'sample_status_____' (already declared at li
ne 31), changing conflicting identifier name to new name sample_status______'. Note: this problem may be caused by importing invalid XML schemas (detected at line 38 in sample.h)

My header file looks such like:

// enum definition
enum status {ok, error};

// method definition
status ns_calc(int a, int b);

Is it a limitation with soapcpp.exe?

Answer 1

The header file you are writting has to follow some gSoap conventions. Therefore the output of the function has to be the last argument. From the documentation:

By convention, all parameters are input parameters except the last. The last parameter is always the output parameter. A struct or class is used to wrap multiple output parameters, see also Section 7.1.9. This last parameter must be a pointer or reference. By contrast, the input parameters support pass by value or by pointer, but not pass by C++ reference.

The relevant part in the header file would look like:

enum ns__status { ok, error };
int ns__calc(xsd__int a, xsd__int b, enum ns__status& out);

Note that this example explicitly uses XML-Schema (xsd__) types, this practice is advised to improve interoperability. The relevant part in the cpp file would look like:

int ns__calc(struct soap* soap, xsd__int a, xsd__int b, enum ns__status& out)
{
    // do something with 'a' and 'b' and set 'out'
    out = ...
    return SOAP_OK;
}