无法在块内引用具有可变修改类型的声明 [英] Cannot refer to declaration with a variably modified type inside block

问题描述

这是我的代码段，我遇到了上述错误.

This is the snippet of my code and i am getting the above mentioned error.

dispatch_async(background_thread, ^{
    cameras camera[10];
    .
    .
    for(int i=0; i<ncam; i++) {
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0),^{
            iPoint subPoints[10];
            subPoints[0].x = camera[i].x + ((int)camera[i].mindist)*cos(camera[i].dir + (camera[i].angle)/2);
            .
            .
            .
        });
    }
});

照相机实际上是C型结构，并且错误是由照相机阵列引起的.有人请帮助我摆脱这个问题.

cameras is actually a C-type structure and the error is with camera array. Someone please help me how to get rid off with this problem.

推荐答案

您的相机位于堆栈中，而Objective-C在带有不支持引用计数的变量的块中表现不佳.尝试在NSObject中移动此数组:

Yours cameras located in stack, and objective-c work badly in blocks with variables that doesn't support reference counting. Try move this array inside NSObject:

@interface TenCameras : NSObject
{
@public
    cameras camera[10];
}
@end

然后您的代码将是这样的:

Then yours code will be something like that:

dispatch_async(background_thread, ^{
    TenCameras tenCameras;
    .
    .
    for(int i=0; i<ncam; i++) {
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0),^{
            iPoint subPoints[10];
            subPoints[0].x = tenCameras->camera[i].x + ((int)tenCameras->camera[i].mindist)*cos(tenCameras->camera[i].dir + (tenCameras->camera[i].angle)/2);
            .
            .
            .
        });
    }
});

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