A FireShotgun

A_FireShotgun is a code pointer used in the attack animation for the Shotgun. It implements the main shotgun firing logic.

does the following:
 * Sets the player into state  so that other players in the game see the player firing a weapon.
 * Activates the weapon's "flash state" that shows the gun-barrel flash.
 * Plays the sound effect DSSHOTGN.
 * Fires seven pellets in the direction that the player is facing (performing autoaim to determine vertical angle).

Uses
The  code pointer appears in the following states in Doom's state table:

Example
The following is an example of how to set the  code pointer in a Dehacked file:

Pointer 21 (Frame 34) Codep Frame = 22

Or using BEX syntax:

[CODEPTR] Frame 1234 = FireShotgun