Error Handling

You may want to react on error messages created by a called function. For instance if you open a file and it cannot be opened.

Check[expr,failexpr] evaluates expr, and returns the result, unless messages were generated, in which case it evaluates and returns failexpr.

Check[expr,failexpr,{s1::t1,s2::t2,…}] checks only for the specified messages.

Check[expr,failexpr,„name“] checks only for messages in the named message group.

Example:

Check[(a=«„hallo“); , Print[„could not open file“]; Exit[]; , {Get::noopen}]