If you take the following code, that comes straight
from the manual of GMP 4.1, and try to compile it with
a strictly conforming C++ compiler, you will see that
it does not compile.
---------------------------------------------
#include <gmpxx.h>
void foo() {
gmp_randclass rg(gmp_randinit_default);
}
---------------------------------------------
The reason is that, while the constructors for `gmp_randclass'
have all been declared to take a C++ function pointer, the
invocation above passes a C function pointer. This is not allowed
by the C++ standard. One possibility to rectify things is the patch
below, which changes the declarations of the constructors.
Of course, the dual change is also possible, the point being
that C linkage and C++ linkage are incompatible.
All the best
Roberto
--
Prof. Roberto Bagnara
Computer Science Group
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara@cs.unipr.it
*** /usr/local/distrib/gmp-4.1/gmpxx.h 2002-05-08 01:09:50.000000000 +0200
--- gmpxx.h 2002-11-05 15:03:05.000000000 +0100
***************
*** 4968,4973 ****
--- 4968,4981 ----
}
};
+ extern "C" typedef void GMP_RANDINIT_DEFAULT(gmp_randstate_t);
+ extern "C" typedef void GMP_RANDINIT_LC_2EXP(gmp_randstate_t,
+ mpz_srcptr,
+ unsigned long int,
+ unsigned long int);
+ extern "C" typedef void GMP_RANDINIT_LC_2EXP_SIZE(gmp_randstate_t,
+ unsigned long int);
+
class gmp_randclass
{
private:
***************
*** 4988,5004 ****
}
// gmp_randinit_default
! gmp_randclass(void (*f)(gmp_randstate_t))
{ f(state); }
// gmp_randinit_lc_2exp
! gmp_randclass(void (*f)(gmp_randstate_t, mpz_srcptr,
! unsigned long int, unsigned long int),
mpz_class z, unsigned long int l1, unsigned long int l2)
{ f(state, z.get_mpz_t(), l1, l2); }
// gmp_randinit_lc_2exp_size
! gmp_randclass(int (*f)(gmp_randstate_t, unsigned long int),
unsigned long int size)
{ f(state, size); }
--- 4996,5011 ----
}
// gmp_randinit_default
! gmp_randclass(GMP_RANDINIT_DEFAULT* f)
{ f(state); }
// gmp_randinit_lc_2exp
! gmp_randclass(GMP_RANDINIT_LC_2EXP* f,
mpz_class z, unsigned long int l1, unsigned long int l2)
{ f(state, z.get_mpz_t(), l1, l2); }
// gmp_randinit_lc_2exp_size
! gmp_randclass(GMP_RANDINIT_LC_2EXP_SIZE* f,
unsigned long int size)
{ f(state, size); }
