WSTP : function name as argument

Questions
, ,
1

I have development my own NDSolve function in C language:

void MyNDSolve ( void odefun (), double *u, double xmin, double xmax)
{
 ...........
}

where Odefun is name of a function coded in C.

I want to be call it from Mathematica.
But how can I specify a function name as argument in the WSTP template ?

:Begin:
:Function:        MyNDSolve
:Pattern:          MyNDSolve[ ??, u_List, xmin_Real, xmax_Real]
:Arguments:     {odefun, u, xmin,xmax}
:ArgumentTypes:   {??, RealList, Real, Real}
:ReturnType:    Manual
:End:

Someone can help me ?