MONDAY, APRIL 20, 2026 GLIBC DIGEST · OPEN-SOURCE SYSTEMS DAILY VOL. 1 · NO. 110
Late Edition · APRIL 20, 2026 · VOL. 1 · NO. 110
The glibc Digest
— A Daily Record of the GNU C Library —
libio Under Review

libio: Seeking feedback on fmemopen_write fix

Rocket Ma is pinging for feedback on a patch to fix `fmemopen_write` in appending condition.

Rocket Ma is requesting feedback on version 2 of a patch that aims to fix fmemopen_write when used in appending condition. The patch’s approach is under discussion, particularly regarding how it handles buffer size and potential inconsistencies with setbuf.

Technical Tradeoffs

  • The proposed fix involves directly setting the buffer to NULL, rejecting `setbuf` requests, and returning `EINVAL` if space is insufficient. This approach may limit flexibility.
  • Alternative approaches, such as adding a specific size of allocated buffer function, may introduce inconsistencies if the user sets the buffer manually.
Filed Under: libiofmemopenappendbugfix