g ++认为我没有传递引用

Question

当我调用一个引用的方法时,g ++抱怨我没有传递引用.我认为呼叫者不必为PBR做任何不同的事情.这是有问题的代码:

//method definition
void addVertexInfo(VertexInfo &vi){vertexInstances.push_back(vi);} 

//method call:
sharedVertices[index]->addVertexInfo(VertexInfo(n1index, n2index));

这是错误:

GLUtils/GLMesh.cpp: In member function 'void GLMesh::addPoly(GLIndexedPoly&)': GLUtils/GLMesh.cpp:110: error: no matching function for call to 'SharedVertexInfo::addVertexInfo(VertexInfo)' GLUtils/GLMesh.h:93: note: candidates are: void SharedVertexInfo::addVertexInfo(VertexInfo&)

Answer 1

VertexInfo(n1index, n2index)创建一个临时VertexInfo对象.临时不能绑定到非const引用.

修改addVertexInfo()函数以获取const引用将解决此问题:

void addVertexInfo(const VertexInfo& vi) { /* ... */ }

通常,如果函数不修改它通过引用获取的参数,它应该采用const引用.