# Set type

Hotkey: Y

The SetType command sets the type of the current item. It can be applied to the following things:

* Function
* Local variable
* Global item (function or data)

If the command is applied to the very first line of the output text, the decompiler will try to detect the current function argument. If the cursor is on an argument declaration, then the argument type will be modified. Otherwise, the current function type will be modified.

In all other cases the item under the cursor will be modified.

When modifying the prototype of the current function you may add or remove function arguments, change the return type, and change the calling convention. If you see that the decompiler wrongly created too many function arguments, you can remove them.

The item type must be specified as a C type declaration. All types defined in the loaded type libraries, all structures in the local types window, all enum definitions in the local types window can be used.

This is a very powerful command. It can change the output dramatically. Use it to remove cast operations from the output and to make it more readable. In some cases, you will need to define structure types in the local types window and only after that use them in the pseudocode window.

NOTE: since the arguments of indirect calls are collected before defining variables, specifying the type of the function pointer may not be enough. Please read [this](/9.1/user-guide/decompiler/tricks.md) for more info.

Since variables and function types are essential, the decompiler uses colors to display them. By default, definite types (set by the user, for example) are displayed in blue while guessed types are displayed in gray. Please note that the guessed types may change if the circumstances change. For example, if the prototype of a called function is changed, the variable that holds its return value may change automatically, unless its type was set by the user.

This command does not rename the operated item, even if you specify the name in the declaration. Please use the [rename](/9.1/user-guide/decompiler/interactive/cmd_rename.md) command for that.

See also: [interactive operation](/9.1/user-guide/decompiler/interactive.md)


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