Problem in converting char * to java objects

Question

Hi All,
When I am trying to compile the following JNI code, I am getting the under-mentioned errors.
<code>
JNIEXPORT jboolean JNICALL Java_XXXAPI_nativeCheckSomeAccess
(JNIEnv *jnv, jobject jobj, jstring fresource, jstring uname){
     jboolean accessible;
     int     ierror;
     // convert jstring to char pointers
     const char resname = (jnv)->GetStringUTFChars(jnv, fresource, 0);
     const char u = (jnv)->GetStringUTFChars(jnv, uname, 0);
     // pass parameters and check access
     int canAccess = checkSomeAccess(resname, user, &ierror);
     if(!ierror && canAccess == 1)
          accessible = true;
     else
          accessible = false;
     // release variables from JNI environment
     (*jnv)->ReleaseStringUTFChars(jnv, fresource, resname);
     (*jnv)->ReleaseStringUTFChars(jnv, uname, u);
     return accessible;
the checkSomeAccess in "someCfile.h" actually looks like this:
int checkSomeAccess(char resname, char u, <enumeration> *ptr_to_enum_containing_integers);
</code>
When compiled the code... I am getting the following errors:
some_jni.c: In function `Java_XXXAPI_nativeCheckSomeAccess':
some_jni.c:65: warning: passing arg 1 of `checkSomeAccess' discards qualifiers from pointer target type
some_jni.c:65: warning: passing arg 2 of `checkSomeAccess' discards qualifiers from pointer target type
some_jni.c:65: warning: passing arg 3 of `checkSomeAccess' from incompatible pointer type
some_jni.c:67: `true' undeclared (first use in this function)
some_jni.c:69: `false' undeclared (first use in this function)
Please tell me, what is the problem here.
thank you,
Ran.

Answer 1

Hi All,
How to convert an enum in C to Java-JNI ? I have the following enum defined in C.
typedef enum{
    ERR_NOERROR=0,
    ERR_INTERNAL,
    ERR_NOOBJECT,
    ERR_INVALIDOBJ,
}error_t;I am using this enum in my C function (in the header file) as:
int isSuccess(char* some_name, error_t *error);Now, while writing the JNI implementation for this, I have actually passed an integer which is giving compile time warning:
int result;
char *sn = (char*)(*env)->GetStringUTFChars(env, jstring_val, 0);
int errorCode;
result = isSuccess(sn, &errorCode);I would like to know, how to represent the enum type in JNI. It would be grateful If you provide an example code snippet.
thanks in advance,
Ran.