diff options
| -rw-r--r-- | lib.c | 15 | ||||
| -rw-r--r-- | txr.1 | 8 |
2 files changed, 18 insertions, 5 deletions
@@ -7571,12 +7571,17 @@ val int_cptr(val cptr) mem_t *cptr_handle(val cptr, val type_sym, val self) { - if (type(cptr) != CPTR) + if (type(cptr) != CPTR) { uw_throwf(error_s, lit("~a: ~s isn't a cptr"), self, cptr, nao); - if (type_sym && cptr->co.cls != type_sym) - uw_throwf(error_s, lit("~a: cptr ~s isn't of type ~s"), self, cptr, - type_sym, nao); - return cptr->co.handle; + } else { + mem_t *ptr = cptr->co.handle; + + if (type_sym && cptr->co.cls != type_sym && (ptr != 0 || cptr->co.cls)) + uw_throwf(error_s, lit("~a: cptr ~s isn't of type ~s"), self, cptr, + type_sym, nao); + + return ptr; + } } mem_t *cptr_get(val cptr) @@ -55456,6 +55456,14 @@ In the reverse direction, when a Lisp object is converted to the parametrized type, its type tag must match .metn type-sym , or else the conversion fails with an error exception. +This rule contains a slight relaxation: a +.code cptr +object with a +.code nil +tag can be converted to a foreign representation using any parametrized type, +if its value is null. In other situations, the +.code cptr-cast +function must be used to coerce the pointer object to the matching type. Note that if .meta type-sym |