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Diffstat (limited to 'src/runtime/HACKING.md')
| -rw-r--r-- | src/runtime/HACKING.md | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/src/runtime/HACKING.md b/src/runtime/HACKING.md index fbf22eeb44..61755241c5 100644 --- a/src/runtime/HACKING.md +++ b/src/runtime/HACKING.md @@ -277,6 +277,25 @@ functions that release the P or may run without a P and Since these are function-level annotations, code that releases or acquires a P may need to be split across two functions. +go:uintptrkeepalive +------------------- + +The //go:uintptrkeepalive directive must be followed by a function declaration. + +It specifies that the function's uintptr arguments may be pointer values that +have been converted to uintptr and must be kept alive for the duration of the +call, even though from the types alone it would appear that the object is no +longer needed during the call. + +This directive is similar to //go:uintptrescapes, but it does not force +arguments to escape. Since stack growth does not understand these arguments, +this directive must be used with //go:nosplit (in the marked function and all +transitive calls) to prevent stack growth. + +The conversion from pointer to uintptr must appear in the argument list of any +call to this function. This directive is used for some low-level system call +implementations. + go:notinheap ------------ |