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std.Thread.setName: use unused code

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I noticed a comment saying that the intent of a code's author was unclear.
What happened is that the author forgot to put the check for whether the
thread is the calling thread (`self.getHandle() ==
std.c.pthread_self()`) in the `if (use_pthreads)`.
If the thread is the calling thread, we use `prctl` to set or get the
thread's name and it does not take a thread id because it knows the id
of the thread we're calling `getName` or `setName` from.
I have found a source saying that using `pthread_setname_np` on either the calling thread
or any other thread by thread id would work too (so we don't need to
call `prctl`) but I was not sure if that is the case on all systems
so we keep using `pthread_setname_np` if we have a
specific thread that is not the thread we're calling from, and `prctl`
otherwise.
This commit is contained in:
r00ster91 2023-02-21 18:09:00 +01:00
parent c9e02d3e69
commit 0b2ee09378
1 changed files with 17 additions and 14 deletions
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31
lib/std/Thread.zig
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@ -62,18 +62,20 @@ pub fn setName(self: Thread, name: []const u8) SetNameError!void {
switch (target.os.tag) {
.linux => if (use_pthreads) {
const err = std.c.pthread_setname_np(self.getHandle(), name_with_terminator.ptr);
switch (err) {
.SUCCESS => return,
.RANGE => unreachable,
else => |e| return os.unexpectedErrno(e),
}
} else if (use_pthreads and self.getHandle() == std.c.pthread_self()) {
// TODO: this is dead code. what did the author of this code intend to happen here?
const err = try os.prctl(.SET_NAME, .{@ptrToInt(name_with_terminator.ptr)});
switch (@intToEnum(os.E, err)) {
.SUCCESS => return,
else => |e| return os.unexpectedErrno(e),
if (self.getHandle() == std.c.pthread_self()) {
// Set the name of the calling thread (no thread id required).
const err = try os.prctl(.SET_NAME, .{@ptrToInt(name_with_terminator.ptr)});
switch (@intToEnum(os.E, err)) {
.SUCCESS => return,
else => |e| return os.unexpectedErrno(e),
}
} else {
const err = std.c.pthread_setname_np(self.getHandle(), name_with_terminator.ptr);
switch (err) {
.SUCCESS => return,
.RANGE => unreachable,
else => |e| return os.unexpectedErrno(e),
}
}
} else {
var buf: [32]u8 = undefined;
@ -177,6 +179,7 @@ pub fn getName(self: Thread, buffer_ptr: *[max_name_len:0]u8) GetNameError!?[]co
else => |e| return os.unexpectedErrno(e),
}
} else if (use_pthreads and self.getHandle() == std.c.pthread_self()) {
// Get the name of the calling thread (no thread id required).
const err = try os.prctl(.GET_NAME, .{@ptrToInt(buffer.ptr)});
switch (@intToEnum(os.E, err)) {
.SUCCESS => return std.mem.sliceTo(buffer, 0),
@ -325,10 +328,10 @@ pub const SpawnError = error{
Unexpected,
};
/// Spawns a new thread which executes `function` using `args` and returns a handle the spawned thread.
/// Spawns a new thread which executes `function` using `args` and returns a handle to the spawned thread.
/// `config` can be used as hints to the platform for now to spawn and execute the `function`.
/// The caller must eventually either call `join()` to wait for the thread to finish and free its resources
/// or call `detach()` to excuse the caller from calling `join()` and have the thread clean up its resources on completion`.
/// or call `detach()` to excuse the caller from calling `join()` and have the thread clean up its resources on completion.
pub fn spawn(config: SpawnConfig, comptime function: anytype, args: anytype) SpawnError!Thread {
if (builtin.single_threaded) {
@compileError("Cannot spawn thread when building in single-threaded mode");