在Apple的文档中说:块文字(即^ {...})是表示块的堆栈本地数据结构的地址.因此,堆栈本地数据结构的范围是封闭的复合语句,因此您应该避免以下示例中显示的模式:
void dontDoThis() {
void (^blockArray[3])(void); // an array of 3 block references
for (int i = 0; i < 3; ++i) {
blockArray[i] = ^{ printf("hello, %d\n", i); };
// WRONG: The block literal scope is the "for" loop.
}
//for example I invoke the block here
blockArray[1]();
}
void dontDoThisEither() {
void (^block)(void);
int i = random():
if (i > 1000) {
block = ^{ printf("got i at: %d\n", i); };
// WRONG: The block literal scope …Run Code Online (Sandbox Code Playgroud)