PR_GetUniqueIdentity 编辑

Asks the runtime to allocate a unique identity for a layer identified by the layer's name.

Syntax

#include <prio.h>

/wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PRDescIdentity PR_GetUniqueIdentity(const char *layer_name);

Parameter

The function has the following parameter:

layer_name

The string associated with the creation of a layer's identity.

Returns

The function returns one of the following values:

• If successful, the /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PRDescIdentity for the layer associated with the string specified in the layer named layer_name.
• If the function cannot allocate enough dynamic memory, it fails and returns the value PR_INVALID_IO_LAYER with the error code PR_OUT_OF_MEMORY_ERROR.

Description

A string may be associated with a layer when the layer is created. PR_GetUniqueIdentity allocates a unique layer identity and associates it with the string. The string can be subsequently passed to /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PR_CreateIOLayerStub to create a new file descriptor of that layer.

Call PR_GetUniqueIdentity only once for any particular layer name. If you're creating a custom I/O layer, cache the result, and then use that cached result every time you call /wiki/en-US/docs/Mozilla/Projects/NSPR/Reference/PR_CreateIOLayerStub.