diff options
Diffstat (limited to 'libraries/base/GHC/IO/Unsafe.hs')
| -rw-r--r-- | libraries/base/GHC/IO/Unsafe.hs | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/libraries/base/GHC/IO/Unsafe.hs b/libraries/base/GHC/IO/Unsafe.hs index 5284dcf887..e6c43e920c 100644 --- a/libraries/base/GHC/IO/Unsafe.hs +++ b/libraries/base/GHC/IO/Unsafe.hs @@ -117,6 +117,10 @@ monadic use of references. There is no easy way to make it impossible once you use 'unsafePerformIO'. Indeed, it is possible to write @coerce :: a -> b@ with the help of 'unsafePerformIO'. So be careful! + +WARNING: If you're looking for "a way to get a 'String' from an 'IO String'", +then 'unsafePerformIO' is not the way to go. Learn about do-notation and the +@<-@ syntax element before you proceed. -} unsafePerformIO :: IO a -> a unsafePerformIO m = unsafeDupablePerformIO (noDuplicate >> m) |