我想使用 C 函数而不是 Objective-C 方法来启动一个新线程。我试过了
[NSThread detachNewThreadSelector: @selector(func) toTarget: nil withObject: id(data)];
我在哪里
void func(void *data) {
// ...
}
和data
是void *
,但我在objc_msgSend
中遇到运行时崩溃,从
-[NSThread initWithTarget:selector:object:]
我能做什么呢?有可能吗?
最佳答案
自己动手:
// In some .h file. #import to make the extension methods 'visible' to your code.
@interface NSThread (FunctionExtension)
+(void)detachNewThreadByCallingFunction:(void (*)(void *))function data:(void *)data;
-(id)initWithFunction:(void (*)(void *))function data:(void *)data;
@end
// In some .m file.
@implementation NSThread (FunctionExtension)
+(void)startBackgroundThreadUsingFunction:(id)object
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
void (*startThreadFunction)(void *) = (void (*)(void *))[[object objectForKey:@"function"] pointerValue];
void *startThreadData = (void *) [[object objectForKey:@"data"] pointerValue];
if(startThreadFunction != NULL) { startThreadFunction(startThreadData); }
[pool release];
pool = NULL;
}
+(void)detachNewThreadByCallingFunction:(void (*)(void *))function data:(void *)data
{
[[[[NSThread alloc] initWithFunction:function data:data] autorelease] start];
}
-(id)initWithFunction:(void (*)(void *))function data:(void *)data
{
return([self initWithTarget:[NSThread class] selector:@selector(startBackgroundThreadUsingFunction:) object:[NSDictionary dictionaryWithObjectsAndKeys:[NSValue valueWithPointer:function], @"function", [NSValue valueWithPointer:data], @"data", NULL]]);
}
@end
注意:我写了上面的代码,并把它放在了公共(public)领域。 (有时律师喜欢这种东西)它也完全未经测试!
如果你能保证线程入口函数也创建一个,你总是可以删除 NSAutoreleasePool
位......但它是无害的,没有任何速度损失,并且可以任意调用C 函数要简单得多。我会说就把它放在那里。
你可以像这样使用它:
void bgThreadFunction(void *data)
{
NSLog(@"bgThreadFunction STARTING!! Data: %p", data);
}
-(void)someMethod
{
// init and then start later...
NSThread *bgThread = [[[NSThread alloc] initWithFunction:bgThreadFunction data:(void *)0xdeadbeef] autorelease];
// ... assume other code/stuff here.
[bgThread start];
// Or, use the all in one convenience method.
[NSThread detachNewThreadByCallingFunction:bgThreadFunction data:(void *)0xcafebabe];
}
运行时:
2009-08-30 22:21:12.529 test[64146:1303] bgThreadFunction STARTING!! Data: 0xdeadbeef
2009-08-30 22:21:12.529 test[64146:2903] bgThreadFunction STARTING!! Data: 0xcafebabe
关于objective-c - C 函数可以用作 Cocoa 中的选择器吗?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/1355045/