ios - How to store a block definition that returns something, in a local variable -

this seems little strange me when block not returns anything, can capture in variable before passing consumer metod. add return value block typedef, start getting waring

scenario 1: block not returns //declaration

typedef void (^myconfigureblock)(myfeedcell *cell, nsindexpath *indexpath); 

//usage

  myconfigureblock block  = ^(myfeedcell *cell, nsindexpath *indexpath){     [cell setactiondelegate:self];     return nil; };  myfeedsource *fds = [[myfeedsource alloc]initwithtableview:self.tableview                                                     configurationblock:block]; [fds seterrormessage:@"no feeds yet. alive?"]; self.feeddatasource = fds; 

every thing works perfect in above piece of code unless go ahead , do:

problem here

typedef myfeedcell* (^myconfigureblock)(myfeedcell *cell, nsindexpath *indexpath); 

now how can re-write following statements there no error. , why not works usual return type?

myconfigureblock block  = ^(myfeedcell *cell, nsindexpath *indexpath){     [cell setactiondelegate:self];     return nil; }; 

the error is

sending 'myfeedcell *' parameter of incompatible type 'myconfigureblock' (aka 'myfeedcell *(^)(myfeedcell *__strong, nsindexpath *__strong)')

the code uses block

- (uitableviewcell*)tableview:(uitableview*)atableview cellforrowatindexpath:(nsindexpath*)indexpath {              self.cellconfigureblock(nil, indexpath); } 

you have include block's return type in block signature because compiler cannot infer block's return type if return nil. try this:

myconfigureblock block = ^ myfeedcell* (myfeedcell *cell, nsindexpath *indexpath){     [cell setactiondelegate:self];     return nil; }; 

note original code not raise compile error if return myfeedcell object because compiler can infer return type:

myconfigureblock block = ^(myfeedcell *cell, nsindexpath *indexpath){     [cell setactiondelegate:self];     return cell; };