Difference between revisions of "User Functions"
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imported>QQuix (Added link to the list of user functions (Category page)) |
imported>QQuix (Added some notes) |
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__NOTOC__ | |||
User-Defined Functions - a feature added with OBSE v18 | User-Defined Functions - a feature added with OBSE v18 | ||
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A function script can contain only one block. The name of the script is the name of the function. | A function script can contain only one block. The name of the script is the name of the function. | ||
Parameters are stored in local variables and must be indicated within {braces} in the function definition. | |||
A set of empty braces indicates the function takes no arguments. | |||
When parsing a function call, the compiler will verify that the number and type of the arguments match those expected by the function's parameter list. | |||
If the called function is specified as a ref variable this validation cannot be performed; it is the scripter's responsibility to ensure the argument list is valid to avoid errors at run-time. | |||
===Notes=== | |||
*Function scripts should never be attached to any object. | |||
*All variables in a function script must be declared before the function body. | |||
*Local variables and argument variables retain their values only until the function returns. | |||
*Numbers, references and strings passed as parameters are copied to their proper local variables. Changing these copies do not change the original variables in the calling script. | |||
*Arrays, on the other hand, are passed as pointers to the original arrays, therefore changes to arrays passed as parameters will persist after the user function returns. | |||
*Clean up | |||
**Strings passed as parameters are destroyed when the function returns. | |||
**Any other string stored in local variables must be explicitly destroyed with [[sv_Destruct]] before the function execution ends (or else they will bloat the savegame). | |||
**Arrays passed as parameters are pointers to the original arrays, so no clean up is necessary (the pointer, itself, is destroyed automatically). | |||
**Local arrays are destroyed automatically when the function execution ends. | |||
**All other local variables (shorts, floats, refs etc.) are also destroyed when the function execution ends. | |||
Functions have some useful properties. | Functions have some useful properties. | ||