Re: libclasspath const/non-const warnings

[Steven Augart]

Michael Koch wrote:
> > -JCL_free_cstring (JNIEnv * env, jstring s, const char *cstr)
> > +JCL_free_cstring (JNIEnv * env, jstring s, char *cstr)
> > {
> >   (*env)->ReleaseStringUTFChars (env, s, cstr);
> > }
>
>
> I would think "cstr" stands for "constant string" but you removed 
> "const". Perhaps you should rename "cstr" to "str".
Logically, you'd think so.  But it's just the counter-part of
JCL_jstring_to_cstring, which converts a Java string into a C
string.  Thus the "cstr".

I converted it to take a non-const pointer because the underlying 
ReleaseStringUTFChars may call free() to release the memory.

I am looking this over more carefully, though, and I see that the JNI
spec defines GetStringUTFChars as returning a "const char *", and 
ReleaseStringUTFChars as taking a "const char *" -- presumably, 
because the designers thought there might be some VM out there that
natively stores strings as UTF?

So, that change was not appropriate, and I have backed it out.  Thanks 
for catching this.

--Steven

--
Steven Augart

Jikes RVM, a free, open source, Virtual Machine:
http://oss.software.ibm.com/jikesrvm

ChangeLog entry:

2004-06-21  Steven Augart  <address@hidden>

        * native/jni/classpath/jcl.h, native/jni/classpath/jcl.c
        (JCL_free_cstring): "cstr" argument back to const.

Index: native/jni/classpath/jcl.c
===================================================================
RCS file: /cvsroot/classpath/classpath/native/jni/classpath/jcl.c,v
retrieving revision 1.10
diff -I*.class -u -r1.10 jcl.c
--- native/jni/classpath/jcl.c  21 Jun 2004 19:39:41 -0000      1.10
+++ native/jni/classpath/jcl.c  21 Jun 2004 21:45:19 -0000
@@ -139,7 +139,7 @@
 }
 
 JNIEXPORT void JNICALL
-JCL_free_cstring (JNIEnv * env, jstring s, char *cstr)
+JCL_free_cstring (JNIEnv * env, jstring s, const char *cstr)
 {
   (*env)->ReleaseStringUTFChars (env, s, cstr);
 }
Index: native/jni/classpath/jcl.h
===================================================================
RCS file: /cvsroot/classpath/classpath/native/jni/classpath/jcl.h,v
retrieving revision 1.8
diff -I*.class -u -r1.8 jcl.h
--- native/jni/classpath/jcl.h  21 Jun 2004 19:39:41 -0000      1.8
+++ native/jni/classpath/jcl.h  21 Jun 2004 21:45:19 -0000
@@ -51,7 +51,8 @@
 JNIEXPORT void JNICALL JCL_free (JNIEnv * env, void *p);
 JNIEXPORT const char *JNICALL JCL_jstring_to_cstring (JNIEnv * env,
                                                      jstring s);
-JNIEXPORT void JNICALL JCL_free_cstring (JNIEnv * env, jstring s, char *cstr);
+JNIEXPORT void JNICALL JCL_free_cstring (JNIEnv * env, jstring s, 
+                                        const char *cstr);
 JNIEXPORT jint JNICALL JCL_MonitorEnter (JNIEnv * env, jobject o);
 JNIEXPORT jint JNICALL JCL_MonitorExit (JNIEnv * env, jobject o);