Hi,

At Sun, 16 Jun 2002 06:25:26 +0900,
Mathieu Bouchard wrote:
> 1. requiring a library that does not contain its Init_foo() method gives a
> strange error message like "tests/test.rb:3:in `require': (null) -
> ./c/lib/i686-linux/foo.so (LoadError)". The "(null)" looks like a %s being
> passed a null pointer.

Calling dlclose() before dln_error() clears error status.  Try
following patches, the first for 1.6 and the second for 1.7.

> 2. how do i get the selector of a message from the C method being called?
> i need to alias a method and then find back with which name it was called.
> this is equivalent to part of RCR #29
> (http://www.rubygarden.org/article.php?sid=89)
> but from C code instead.

You can get the ID with rb_frame_last_func().

> 3. how do i create a Proc from a C function pointer? what should be the
> signature of that function? VALUE (*)(int,VALUE*,VALUE) ?

In 1.7,
VALUE rb_proc_new _((VALUE (*)(ANYARGS/* VALUE yieldarg[, VALUE procarg] */), VALUE));

In 1.6, you can create an object and its singleton method, then
use Kernel#method and Method#to_proc.


Index: dln.c
===================================================================
RCS file: /cvs/ruby/src/ruby/dln.c,v
retrieving revision 1.15.2.12
diff -u -2 -p -r1.15.2.12 dln.c
--- dln.c	2002/03/25 02:37:07	1.15.2.12
+++ dln.c	2002/06/16 04:06:24
@@ -11,6 +11,5 @@
 **********************************************************************/
 
-#include "config.h"
-#include "defines.h"
+#include "ruby.h"
 #include "dln.h"
 
@@ -1225,4 +1224,9 @@ dln_load(file)
     const char *file;
 {
+#if !defined(_AIX) && !defined(NeXT)
+    const char *error = 0;
+#define DLN_ERROR() (error = dln_strerror(), strcpy(ALLOCA_N(char, strlen(error) + 1), error))
+#endif
+
 #if defined _WIN32 && !defined __CYGWIN__
     HINSTANCE handle;
@@ -1240,4 +1244,5 @@ dln_load(file)
     /* Load file */
     if ((handle = LoadLibrary(winfile)) == NULL) {
+	error = dln_strerror();
 	goto failed;
     }
@@ -1252,4 +1257,5 @@ dln_load(file)
 #ifdef USE_DLN_A_OUT
     if (load(file) == -1) {
+	error = dln_strerror();
 	goto failed;
     }
@@ -1276,8 +1282,10 @@ dln_load(file)
 	/* Load file */
 	if ((handle = (void*)dlopen(file, RTLD_LAZY|RTLD_GLOBAL)) == NULL) {
+	    error = dln_strerror();
 	    goto failed;
 	}
 
 	if ((init_fct = (void(*)())dlsym(handle, buf)) == NULL) {
+	    error = DLN_ERROR();
 	    dlclose(handle);
 	    goto failed;
@@ -1505,5 +1513,5 @@ dln_load(file)
 #if !defined(_AIX) && !defined(NeXT)
   failed:
-    rb_loaderror("%s - %s", dln_strerror(), file);
+    rb_loaderror("%s - %s", error, file);
 #endif
 }

Index: dln.c
===================================================================
RCS file: /cvs/ruby/src/ruby/dln.c,v
retrieving revision 1.34
diff -u -2 -p -r1.34 dln.c
--- dln.c	2002/05/14 06:22:25	1.34
+++ dln.c	2002/06/16 04:04:54
@@ -11,6 +11,5 @@
 **********************************************************************/
 
-#include "config.h"
-#include "defines.h"
+#include "ruby.h"
 #include "dln.h"
 
@@ -1242,4 +1241,9 @@ dln_load(file)
     const char *file;
 {
+#if !defined(_AIX) && !defined(NeXT)
+    const char *error = 0;
+#define DLN_ERROR() (error = dln_strerror(), strcpy(ALLOCA_N(char, strlen(error) + 1), error))
+#endif
+
 #if defined _WIN32 && !defined __CYGWIN__
     HINSTANCE handle;
@@ -1257,4 +1261,5 @@ dln_load(file)
     /* Load file */
     if ((handle = LoadLibrary(winfile)) == NULL) {
+	error = dln_strerror();
 	goto failed;
     }
@@ -1271,4 +1276,5 @@ dln_load(file)
 #ifdef USE_DLN_A_OUT
     if (load(file) == -1) {
+	error = dln_strerror();
 	goto failed;
     }
@@ -1295,4 +1301,5 @@ dln_load(file)
 	/* Load file */
 	if ((handle = (void*)dlopen(file, RTLD_LAZY|RTLD_GLOBAL)) == NULL) {
+	    error = dln_strerror();
 	    goto failed;
 	}
@@ -1301,4 +1308,5 @@ dln_load(file)
 	free(buf);
 	if (init_fct == NULL) {
+	    error = DLN_ERROR();
 	    dlclose(handle);
 	    goto failed;
@@ -1539,8 +1547,10 @@ dln_load(file)
 
 	if ((handle = (void*)dlopen(fname, 0)) == NULL) {
+	    error = dln_strerror();
 	    goto failed;
 	}
 
 	if ((init_fct = (void (*)())dlsym(handle, buf)) == NULL) {
+	    error = DLN_ERROR();
 	    dlclose(handle);
 	    goto failed;
@@ -1560,5 +1570,5 @@ dln_load(file)
 #if !defined(_AIX) && !defined(NeXT)
   failed:
-    rb_loaderror("%s - %s", dln_strerror(), file);
+    rb_loaderror("%s - %s", error, file);
 #endif
     return 0;			/* dummy return */


-- 
Nobu Nakada