I am implementing a user-level thread lib using ucontext_t
. I am linking threads to the scheduler thread via uc_link
, however, we need to get the return value on some occasions. I don't know how to get the return value as the contexts are separate.
The only way I can think of accessing the return value is by somehow going to the stack of that context and finding where the return value would be. However, this seems like a formula for disaster and weird errors.
Get return value from ucontext as it terminates
332 views Asked by beans At
1
There are 1 answers
Related Questions in C
- new thread blocks main thread
- Extracting viewCount & SubscriberCount from YouTube API V3 for a given channel, where channelID does not equal userID
- Display images on Django Template Site
- Difference between list() and dict() with generators
- How can I serialize a numpy array while preserving matrix dimensions?
- Protractor did not run properly when using browser.wait, msg: "Wait timed out after XXXms"
- Why is my program adding int as string (4+7 = 47)?
- store numpy array in mysql
- how to omit the less frequent words from a dictionary in python?
- Update a text file with ( new words+ \n ) after the words is appended into a list
Related Questions in PTHREADS
- new thread blocks main thread
- Extracting viewCount & SubscriberCount from YouTube API V3 for a given channel, where channelID does not equal userID
- Display images on Django Template Site
- Difference between list() and dict() with generators
- How can I serialize a numpy array while preserving matrix dimensions?
- Protractor did not run properly when using browser.wait, msg: "Wait timed out after XXXms"
- Why is my program adding int as string (4+7 = 47)?
- store numpy array in mysql
- how to omit the less frequent words from a dictionary in python?
- Update a text file with ( new words+ \n ) after the words is appended into a list
Related Questions in UCONTEXT
- new thread blocks main thread
- Extracting viewCount & SubscriberCount from YouTube API V3 for a given channel, where channelID does not equal userID
- Display images on Django Template Site
- Difference between list() and dict() with generators
- How can I serialize a numpy array while preserving matrix dimensions?
- Protractor did not run properly when using browser.wait, msg: "Wait timed out after XXXms"
- Why is my program adding int as string (4+7 = 47)?
- store numpy array in mysql
- how to omit the less frequent words from a dictionary in python?
- Update a text file with ( new words+ \n ) after the words is appended into a list
Popular Questions
- How do I undo the most recent local commits in Git?
- How can I remove a specific item from an array in JavaScript?
- How do I delete a Git branch locally and remotely?
- Find all files containing a specific text (string) on Linux?
- How do I revert a Git repository to a previous commit?
- How do I create an HTML button that acts like a link?
- How do I check out a remote Git branch?
- How do I force "git pull" to overwrite local files?
- How do I list all files of a directory?
- How to check whether a string contains a substring in JavaScript?
- How do I redirect to another webpage?
- How can I iterate over rows in a Pandas DataFrame?
- How do I convert a String to an int in Java?
- Does Python have a string 'contains' substring method?
- How do I check if a string contains a specific word?
Popular Tags
Trending Questions
- UIImageView Frame Doesn't Reflect Constraints
- Is it possible to use adb commands to click on a view by finding its ID?
- How to create a new web character symbol recognizable by html/javascript?
- Why isn't my CSS3 animation smooth in Google Chrome (but very smooth on other browsers)?
- Heap Gives Page Fault
- Connect ffmpeg to Visual Studio 2008
- Both Object- and ValueAnimator jumps when Duration is set above API LvL 24
- How to avoid default initialization of objects in std::vector?
- second argument of the command line arguments in a format other than char** argv or char* argv[]
- How to improve efficiency of algorithm which generates next lexicographic permutation?
- Navigating to the another actvity app getting crash in android
- How to read the particular message format in android and store in sqlite database?
- Resetting inventory status after order is cancelled
- Efficiently compute powers of X in SSE/AVX
- Insert into an external database using ajax and php : POST 500 (Internal Server Error)
An execution context such as is represented by
ucontext_t
has no return value. This is implicit in the behavior when the entry-point function terminates (the successor context, if any, is activated), and explicit in the signature of the entry-point function (it returnsvoid
).Note also that the entry-point function must additionally be non-variadic, unlike
makecontext()
itself, though it can take any fixed number of arguments. The caller ofmakecontext
is obligated to specify the correct argument count and that manyint
arguments.If you want to communicate data between contexts then you should write it or a pointer to it in some shared memory location from which you can later, in a different context, retrieve it. Presumably, in this case that would be somewhere in the metadata that your lib maintains for each thread.
If the data in question are the return value of some function, then that function cannot be the context's entry-point. In that case (and for other reasons, too) you may want to avoid using functions provided by the user as ucontext entry points. Instead, use a function provided internally by the library that knows how to bootstrap to the user function and what to do when it returns.