| 1 | ---
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| 2 | default_highlighter: oils-sh
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| 3 | ---
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| 4 | 
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| 5 | Portability
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| 6 | ===========
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| 7 | 
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| 8 | What does your platform need to run Oils?
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| 9 | 
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| 10 | These are some notes that supplement [INSTALL](INSTALL.html).
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| 11 | 
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| 12 | <div id="toc">
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| 13 | </div>
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| 14 | 
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| 15 | ## Issues in the core of Oils
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| 16 | 
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| 17 | ### GNU libc for extended globs
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| 18 | 
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| 19 | For matching extended globs like `@(*.cc|*.h)`, Oils relies on GNU libc
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| 20 | support.
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| 21 | 
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| 22 | - This is not a POSIX feature.
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| 23 | - It's also unlike bash, which has its own extended glob support.
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| 24 | 
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| 25 | TODO: when using other libc, using this syntax should be an error.
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| 26 | 
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| 27 | ### Atomic Assignments
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| 28 | 
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| 29 | The signal handler assumes that int and pointer assignments are atomic.  This
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| 30 | is a common and widespread assumption.
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| 31 | 
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| 32 | - Related: [Atomic vs. Non-Atomic
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| 33 |   Operations](https://preshing.com/20130618/atomic-vs-non-atomic-operations/)
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| 34 |   by Jeff Preshing
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| 35 | 
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| 36 | <!--
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| 37 | As of 2024, the GC object layout doesn't depend on endian-ness.
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| 38 | 
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| 39 | Tagged pointers may change this.  A value may be either a pointer, which
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| 40 | implies its least significant bits are zero, or an immediate value.
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| 41 | 
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| 42 | We will have some #ifdef for it.
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| 43 | -->
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| 44 | 
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| 45 | ## Extra Features
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| 46 | 
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| 47 | ### USDT - Userland Statically-Defined Tracing
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| 48 | 
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| 49 | Our C++ code has `DTRACE_PROBE()` macros, which means we can use tools like
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| 50 | `bpftrace` on Linux to make low-overhead queries of runtime behavior.
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| 51 | 
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| 52 | The probe names and locations aren't stable across releases.
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| 53 | 
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| 54 | ## "Enums" that are often extended
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| 55 | 
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| 56 | Different Unix implementations often extend:
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| 57 | 
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| 58 | - the list of signals 
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| 59 | - the list of [ulimit][] resources, which correspond to flags
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| 60 | 
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| 61 | [ulimit]: ref/chap-builtin-cmd.html#ulimit
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| 62 | 
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| 63 | ## Unicode
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| 64 | 
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| 65 | Strings in Oils are byte strings, which are often UTF-8 encoded.
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| 66 | 
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| 67 | We use `libc` functions that may depend on the global locale setting, like
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| 68 | `glob()`.  We currently assume your libc is configured to use UTF-8.
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| 69 | 
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| 70 | See the [Unicode doc][] for details on Unicode-aware operations.
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| 71 | 
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| 72 | [Unicode doc]: unicode.html
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| 73 | 
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| 74 | <!--
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| 75 | 
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| 76 | TODO: ./configure could detect some of these
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| 77 | -->
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