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authorLudovic Courtès <ludo@gnu.org>2010-04-09 00:30:10 +0200
committerLudovic Courtès <ludo@gnu.org>2010-04-09 00:32:15 +0200
commit01ad5a7ba9edb5d8c96567ed80ea1a34019c5338 (patch)
tree0e99da198557e8718718377432f0771c45f7025a /libguile/foreign.c
parent4551e860f02244ffb3858c941319f1613bac40e4 (diff)
downloadguile-01ad5a7ba9edb5d8c96567ed80ea1a34019c5338.tar.gz
Raise an error when attempting to modify the value of `%null-pointer'.
* libguile/foreign.c (sym_null_pointer_error): New variable. (null_pointer_error): New function. (scm_foreign_set_x): Raise an error if attempting to modify NULL_POINTER. (scm_foreign_to_bytevector): Use `null_pointer_error ()' instead of `scm_misc_error ()'. * test-suite/tests/foreign.test: New file. * test-suite/Makefile.am (SCM_TESTS): Add tests/foreign.test. * test-suite/lib.scm (exception:null-pointer-error): New variable.
Diffstat (limited to 'libguile/foreign.c')
-rw-r--r--libguile/foreign.c18
1 files changed, 17 insertions, 1 deletions
diff --git a/libguile/foreign.c b/libguile/foreign.c
index 0d6b67000..eaeea6c90 100644
--- a/libguile/foreign.c
+++ b/libguile/foreign.c
@@ -52,6 +52,7 @@ SCM_SYMBOL (sym_size_t, "size_t");
SCM_SYMBOL (sym_asterisk, "*");
SCM_SYMBOL (sym_null, "%null-pointer");
+SCM_SYMBOL (sym_null_pointer_error, "null-pointer-error");
/* The cell representing the null pointer. */
static const scm_t_bits null_pointer[2] =
@@ -60,6 +61,15 @@ static const scm_t_bits null_pointer[2] =
0
};
+/* Raise a null pointer dereference error. */
+static void
+null_pointer_error (const char *func_name)
+{
+ scm_error (sym_null_pointer_error, func_name,
+ "null pointer dereference", SCM_EOL, SCM_EOL);
+}
+
+
static SCM cif_to_procedure (SCM cif, SCM func_ptr);
@@ -161,6 +171,12 @@ SCM_DEFINE (scm_foreign_set_x, "foreign-set!", 2, 0, 0,
scm_t_uint8 *ptr;
SCM_VALIDATE_FOREIGN (1, foreign);
+
+ if (SCM_UNLIKELY (scm_is_eq (foreign, PTR2SCM (&null_pointer))))
+ /* Attempting to modify the pointer value of NULL_POINTER (which is
+ read-only anyway), so raise an error. */
+ null_pointer_error (FUNC_NAME);
+
ptr = SCM_FOREIGN_POINTER (foreign, scm_t_uint8);
ftype = SCM_FOREIGN_TYPE (foreign);
@@ -237,7 +253,7 @@ SCM_DEFINE (scm_foreign_to_bytevector, "foreign->bytevector", 1, 3, 0,
ptr = SCM_FOREIGN_POINTER (foreign, scm_t_int8);
if (SCM_UNLIKELY (ptr == NULL))
- scm_misc_error (FUNC_NAME, "null pointer dereference", SCM_EOL);
+ null_pointer_error (FUNC_NAME);
if (SCM_UNBNDP (uvec_type))
btype = SCM_ARRAY_ELEMENT_TYPE_VU8;