One or more of these values can be combined using the OR operator.
This is the default option for streams; it requests that the include_path is not to be searched for the requested file.
Requests that the include_path is to be searched for the requested file.
Requests that registered URL wrappers are to be ignored when opening the stream. Other non-URL wrappers will be taken into consideration when decoding the path. There is no opposite form for this flag; the streams API will use all registered wrappers by default.
On Windows systems, this is equivalent to IGNORE_URL. On all other systems, this flag has no effect.
Requests that the underlying stream implementation perform safe_mode checks on the file before opening the file. Omitting this flag will skip safe_mode checks and allow opening of any file that the PHP process has rights to access.
If this flag is set, and there was an error during the opening of the file or URL, the streams API will call the php_error function for you. This is useful because the path may contain username/password information that should not be displayed in the browser output (it would be a security risk to do so). When the streams API raises the error, it first strips username/password information from the path, making the error message safe to display in the browser.
This flag is useful when your extension really must be able to randomly seek around in a stream. Some streams may not be seekable in their native form, so this flag asks the streams API to check to see if the stream does support seeking. If it does not, it will copy the stream into temporary storage (which may be a temporary file or a memory stream) which does support seeking. Please note that this flag is not useful when you want to seek the stream and write to it, because the stream you are accessing might not be bound to the actual resource you requested.
Note: If the requested resource is network based, this flag will cause the opener to block until the whole contents have been downloaded.
If your extension is using a third-party library that expects a FILE* or file descriptor, you can use this flag to request the streams API to open the resource but avoid buffering. You can then use php_stream_cast() to retrieve the FILE* or file descriptor that the library requires.
The is particularly useful when accessing HTTP URLs where the start of the actual stream data is found after an indeterminate offset into the stream.
Since this option disables buffering at the streams API level, you may experience lower performance when using streams functions on the stream; this is deemed acceptable because you have told streams that you will be using the functions to match the underlying stream implementation. Only use this option when you are sure you need it.