CODEWITHSUNDEEP
swig
lofidevops
lofidevops

Reputation: 16942

Why does SWIG fail to parse a template / struct?

I am trying to wrap a .h file using SWIG with the following really simple interface file:

%module example
%{
/* Includes the header in the wrapper code */
#include "../pointmatcher/PointMatcher.h"
%}

/* Parse the header file to generate wrappers */
%include "../pointmatcher/PointMatcher.h"

The wrapping attempt fails with the following error:

C:\Data\Projects\lpm-source\libpointmatcher-swig\wrapper>C:\Data\Downloads\swigw
in-3.0.5\swig.exe -csharp -cpperraswarn example.i
..\pointmatcher\PointMatcher.h(61) : Warning 205: CPP #error ""You need libnabo
version 1.0.6 or greater"".
..\pointmatcher\PointMatcher.h(130) : Error: Syntax error in input(1).

The line in question is:

template<typename T>
struct PointMatcher  <-- this line
{

from this file: https://github.com/ethz-asl/libpointmatcher/blob/master/pointmatcher/PointMatcher.h#L130

Why is the SWIG parsing failing here?

Upvotes: 0

Views: 157

Answers (1)

m7thon
m7thon

Reputation: 3043

Swig is parsing the file as a C file instead of C++, and does not understand the template keyword. Try:

swig -c++ -csharp -cpperraswarn example.i

See the swig documentation on wrapping C++.

Also, the function like macros DEF_REGISTRAR(...) and DEF_REGISTRAR_IFACE(...) will confuse swig. So either %include the file where these are defined, or just define them away by adding 

#define DEF_REGISTRAR_IFACE(...)
#define DEF_REGISTRAR(...)

before the %include "../pointmatcher/PointMatcher.h".

Upvotes: 1

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