> On Dec 29, 2015, at 1:22 PM, Jonas Fredriksson via swift-users
> <[email protected]> wrote:
>
> second, to read a file I tried fopen from Glibc but i requires
> "UnsafePointer<Int8>". how do I declare that, ie var file:
> UnsafePointer<Int8>?
You probably wouldn’t declare a variable of that type. Instead just pass a
String for that parameter — the compiler will convert to a C string for you.
For now the best documentation comes from the Using Swift With Cocoa And
Objective-C book, which has a section on plain C APIs:
Constant Pointers
When a function is declared as taking a UnsafePointer<Type> argument,
it can accept any of the following:
...
* A String value, if Type is Int8 or UInt8. The string will
automatically be converted to UTF8 in a buffer that lasts for the duration of
the call.
Whether that’s appropriate for fopen() depends on whether the Linux filesystem
APIs use UTF-8 encoding. (Sorry, I don’t know Linux well enough to say.) If
they don’t, you’ll have trouble with filenames containing non-ASCII characters;
in that case you’d need to write a function to encode the String into a byte
array in the right encoding, and then pass that to fopen().
—Jens_______________________________________________
swift-users mailing list
[email protected]
https://lists.swift.org/mailman/listinfo/swift-users
