Skip to content

Create SHM segments 0666 #61

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
mikelangmayr merged 1 commit into from
Nov 3, 2026
Merged

Create SHM segments 0666 #61

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 2 additions & 1 deletion docs/configuration/frame-outputs.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,8 @@ Frame geometry is deliberately not a key. An ImageStreamIO stream's geometry is
lifetime, so the writer recreates the stream whenever the geometry changes from what is allocated.

Unlike the FITS writer, this output posts a semaphore per frame, so it is the right attachment point
for anything that has to wake up on every frame.
for anything that has to wake up on every frame. The semaphores live inside the segment, so a reader
opens it read-write; segments are created `0666` so any local user can attach.

### Readers

Expand Down
2 changes: 1 addition & 1 deletion utils/shared_memory_writer.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@
namespace {

constexpr int NUM_KEYWORDS = 3; // FRAMENO, TIMESTMP, SEQNUM
constexpr mode_t SEGMENT_MODE = 0664; // group-writable so a co-user can clean up a leftover
constexpr mode_t SEGMENT_MODE = 0666; // readers open read-write to wait on the in-segment semaphores

void set_long_keyword(IMAGE_KEYWORD &keyword, const char *name, int64_t value,
const char *comment) {
Expand Down
Loading