Question

I have two questions.

1. How to create a NSFileHandle object with the FILE* instance?

2. How to create a NSData object with the void* instance?

I am sorry there’s little information without context.

Just refer to my recent question. Weird behavior of fopen on ios I cannot use the native fopen function to create or to write the content into a file.

As a result, I just want to use the api in the ios framework and wrap the code of fopen and fwrite and such staff. So I should convert the FILE* object into NSFileHandle or something that can manipulate the file. Also the content which is handled with void* should be converted to the data format that can be accepted in the ios framework. And I think NSData should be the choice.

Answer 1

As for FILE* to NSFileHandle, I found this mailing list question that perfectly matches what you need. Relevant code:

FILE *fp;
NSFileHandle *p;

fp = fopen( "foo", "r");
p = [[[NSFileHandle alloc] initWithFileDescriptor:fileno( fp)
closeOnDealloc:YES] autorelease];

And it comes with a lovely warning from the answerer:

Be careful not to read from fp, because stdio caches.

EDIT: As for void* to NSData, I think you want NSData's -initWithBytesNoCopy:Length:freeWhenDone:. See this related question on how to use it.