# spSetDefaultDecisionFunction

Install a global decision function to be called for every marker.

### Synopsis

`Err spSetDefaultDecisionFunction (SPPlayer *player,SPDecisionFunction decisionFunc, void *decisionData)`

### Description

Install a global decision function that is to be called when the player reaches each marker. This can be used as a way to do some common operation at multiple locations during playback (e.g. processing a script).

Clear the global decision function with `spClearDefaultDecisionFunction()`.

### Arguments

player
  SPPlayer to which to install default decision function.

decisionFunc
  An SPDecisionFunction to install, or NULL to clear.

decisionData
  A pointer to client-supplied data to be passed to decisionFunc when called. Can be NULL.

### Return Value

Non-negative value on success; negative error code on failure.

### Notes

The player normally optimizes reading data from disc by ignoring markers that have neither a branch destination nor a marker decision function. When a default decision function is installed, the player must interrupt reading data from disc in preparation for a potential branch at EVERY marker, even if the default decision function does nothing. This can severely impact performance depending on the placement of markers.

### Implementation

Library call implemented in music.lib V24.

### Associated Files

soundplayer.h, music.lib

### See Also

``spClearMarkerDecisionFunction`(), spSetMarkerDecisionFunction(), SPDecisionFunction`