mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2025-02-21 06:30:16 +00:00
220c5ca8f4
Most Unix-like operating systems guarantee that the file descriptor is closed after a call to close(2), even if close comes back with EINTR. For these systems, calling close _again_ will either do nothing or close some other file descriptor open(2)'d by another thread. (Linux) However, some operating systems do not have this behavior. They require at least another call to close(2) before guaranteeing that the descriptor is closed. (HP-UX) And some operating systems have an unpredictable blend of the two behaviors! (xnu) Avoid this disaster by blocking all signals before we call close(2). This ensures that a signal will not be delivered to the thread and close(2) will not give us back EINTR. We restore the signal mask once the operation is done. N.B. This isn't a problem on Windows, it doesn't have a notion of EINTR because signals always get delivered to dedicated signal handling threads. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219189 91177308-0d34-0410-b5e6-96231b3b80d8
llvm/lib/Support/Unix README =========================== This directory provides implementations of the lib/System classes that are common to two or more variants of UNIX. For example, the directory structure underneath this directory could look like this: Unix - only code that is truly generic to all UNIX platforms Posix - code that is specific to Posix variants of UNIX SUS - code that is specific to the Single Unix Specification SysV - code that is specific to System V variants of UNIX As a rule, only those directories actually needing to be created should be created. Also, further subdirectories could be created to reflect versions of the various standards. For example, under SUS there could be v1, v2, and v3 subdirectories to reflect the three major versions of SUS.