# GRC: set order of block instantiations **URL:** \ **Category:** GNU Radio\ **Created:** [October 11, 2012, 9:04pm UTC](https://www.ruby-forum.com/t/grc-set-order-of-block-instantiations/223632 "2012-10-11T21:04:40Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![aris](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/258eb7/32.png) [@aris](https://www.ruby-forum.com/u/aris)\ **Post date:** [October 11, 2012, 9:04pm UTC](https://www.ruby-forum.com/t/grc-set-order-of-block-instantiations/223632/1 "2012-10-11T21:04:40Z")
Hi list, is there a way to set the order of block instantiations in GNU Radio companion? The reason I am asking is, that I want to pass one block as a parameter to another block to get access to its methods. Is there an easier way to do this? Somehow related: Variables configured in GRC are defined before the block instantiations. Is it possible to tell GRC where in the final python script a variable should be defined? Best regards Gerald ---
**Author:** ![gerald\_b](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/b2d939/32.png) [@gerald\_b](https://www.ruby-forum.com/u/gerald_b)\ **Post date:** [October 13, 2012, 3:40am UTC](https://www.ruby-forum.com/t/grc-set-order-of-block-instantiations/223632/2 "2012-10-13T03:40:01Z")
On 10/11/2012 12:03 PM, Gerald B. wrote: > Hi list, > > is there a way to set the order of block instantiations in GNU Radio > companion? > The reason I am asking is, that I want to pass one block as a parameter > to another block to get access to its methods. Is there an easier way to > do this? I think the order is either 1) alphabetical or 2) the z dimension of the blocks in the flowgrah. > Somehow related: Variables configured in GRC are defined before the > block instantiations. Is it possible to tell GRC where in the final > python script a variable should be defined? The variable blocks are sorted by order of dependency amongst each other. -josh ---
**Author:** ![gerald\_b](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/b2d939/32.png) [@gerald\_b](https://www.ruby-forum.com/u/gerald_b)\ **Post date:** [October 15, 2012, 9:11pm UTC](https://www.ruby-forum.com/t/grc-set-order-of-block-instantiations/223632/3 "2012-10-15T21:11:07Z")
On 11.10.2012 21:03, Gerald B. wrote: > is there a way to set the order of block instantiations in GNU Radio > companion? > The reason I am asking is, that I want to pass one block as a parameter > to another block to get access to its methods. Is there an easier way to > do this? > Just for future reference, I found out that, at least for my purposes, > there already exists an elegant way to access a block’s methods. It is > possible to define a “function probe” in GNU Radio companion which > periodically calls a block’s method and saves the result as a variable. Best regards Gerald ---
**Author:** ![gerald\_b](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/b2d939/32.png) [@gerald\_b](https://www.ruby-forum.com/u/gerald_b)\ **Post date:** [October 15, 2012, 9:45pm UTC](https://www.ruby-forum.com/t/grc-set-order-of-block-instantiations/223632/4 "2012-10-15T21:45:00Z")
On 10/15/2012 12:10 PM, Gerald B. wrote: > On 11.10.2012 21:03, Gerald B. wrote: > > > is there a way to set the order of block instantiations in GNU Radio > > companion? > > The reason I am asking is, that I want to pass one block as a parameter > > to another block to get access to its methods. Is there an easier way to > > do this? > > Just for future reference, I found out that, at least for my purposes, > > there already exists an elegant way to access a block’s methods. It is > > possible to define a “function probe” in GNU Radio companion which > > periodically calls a block’s method and saves the result as a variable. Sorry, should have mentioned that too! Function probe gets around this by having a try/catch in its loop so the block to be probed doesnt have to yet be instantiated when the thread starts. -josh