Casting data type...please help

[Dimension]

#define UNICODE
#include <jni.h>
#include "AcrobatFile.h"
#include <windows.h>

void launchAcrobat(char fileName[256]);

JNIEXPORT void JNICALL Java_AcrobatFile_PrintAcrobatFile
(JNIEnv *env, jobject obj, jstring fileName)
{
char acrobatFileName[256];

acrobatFileName = env->GetStringChars(fileName,0);

launchAcrobat(acrobatFileName);

acrobatFileName = env->ReleaseStringChars(fileName,acrobatFileName);
}

I'm trying to make the following code work but i keep getting the following errors

[ error C2440: '=' : cannot convert from 'const unsigned short *' to 'char [256]'
[error C2664: 'ReleaseStringChars' : cannot convert parameter 2 from 'char [256]' to 'const unsigned short *'

My question is. How do i convert acrobatFileName[256] to a const unsigned short *? Really appreciate the help. Been stuck on this for a while now. Thanks!

[HarryW]

If you declare a string as an array of characters on the stack, like this:

char acrobatFileName[256];

then what you have actually done is reserved 256 bytes on the stack for your app, and got yourself a constant pointer to the first byte.

You can't just reassign arrays using the = operator. You have to assign each element individual, or copy a whole block of memory over, or use a utility function (like strcpy() for instance) to do it for you.

Anyway, it seems you are also having some type problems.

char[] is in this case actually exactly the same as const unsigned short *, on 32 bit Windows at least. You should be able to do a simple cast in this case to let the compiler know that you know what you're doing:

strcpy(acrobatFileName, (char *)(env->GetStringChars(fileName,0)));

You may need to include string.h to get the strcpy() function.

[parksie]

Don't you have to use Unicode with Java? That would explain the "short" part of it...

[CornedBee]

parksie hit it straight:

void launchAcrobat(wchar_t *fileName); 

JNIEXPORT void JNICALL Java_AcrobatFile_PrintAcrobatFile 
(JNIEnv *env, jobject obj, jstring fileName) 
{ 
wchar_t acrobatFileName[256]; 

acrobatFileName = env->GetStringChars(fileName,0); 

launchAcrobat(acrobatFileName); 

acrobatFileName = env->ReleaseStringChars(fileName,acrobatFileName); 
}

You must use UNICODE characters.

Harry: those are NOT the same, never have been and never will be. Don't make that mistake, it can cause strange and hard-to-find errors.