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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/user-guide/03-convenience-features.md | 65 | ||||
| -rw-r--r-- | docs/user-guide/toc.html | 1 |
2 files changed, 66 insertions, 0 deletions
diff --git a/docs/user-guide/03-convenience-features.md b/docs/user-guide/03-convenience-features.md index 5646292aa..d522daf81 100644 --- a/docs/user-guide/03-convenience-features.md +++ b/docs/user-guide/03-convenience-features.md @@ -793,6 +793,71 @@ by using the `[ForceInline]` decoration: int f(int x) { return x + 1; } ``` +Error handling +----------------- + +Slang supports an error handling mechanism that is superficially similar to +exceptions in many other languages, but has some unique characteristics. + +In contrast to C++ exceptions, this mechanism makes the control flow of errors +more explicit, and the performance charasteristics are similar to adding an +if-statement after every potentially throwing function call to check and handle +the error. + +In order to be able to throw an error, a function must declare the type of that +error with `throws`: +``` +enum MyError +{ + Failure, + CatastrophicFailure +} + +int f() throws MyError +{ + if (computerIsBroken()) + throw MyError.CatastrophicFailure; + return 42; +} +``` +Currently, functions may only throw a single type of error. + +To call a function that may throw, you must prepend it with `try`: + +``` +let result = try f(); +``` + +If you don't catch the `try`, related errors are re-thrown and the calling +function must declare that it `throws` that error type: + +``` +void g() throws MyError +{ + // This would not compile if `g()` wasn't declared to throw MyError as well. + let result = try f(); + printf("Success: %d\n", result); +} +``` + +To catch an error, you can use a `do-catch` statement: + +``` +void g() +{ + do + { + let result = try f(); + printf("Success: %d\n", result); + } + catch(err: MyError) + { + printf("Not good!\n"); + } +} +``` + +You can chain multiple catch statements for different types of errors. Special Scoping Syntax ------------------- diff --git a/docs/user-guide/toc.html b/docs/user-guide/toc.html index 47e0c05ad..c83f36282 100644 --- a/docs/user-guide/toc.html +++ b/docs/user-guide/toc.html @@ -49,6 +49,7 @@ <li data-link="convenience-features#extensions"><span>Extensions</span></li> <li data-link="convenience-features#multi-level-break"><span>Multi-level break</span></li> <li data-link="convenience-features#force-inlining"><span>Force inlining</span></li> +<li data-link="convenience-features#error-handling"><span>Error handling</span></li> <li data-link="convenience-features#special-scoping-syntax"><span>Special Scoping Syntax</span></li> <li data-link="convenience-features#user-defined-attributes-experimental"><span>User Defined Attributes (Experimental)</span></li> </ul> |
