std: integrate Io.Threaded with environment variables

* std.option allows overriding the debug Io instance
* if the default is used, start code initializes environ and argv0

also fix some places that needed recancel(), thanks mlugg!

See #30562

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/std/start.zig b/lib/std/start.zig
index 64a1c17175..5a3e39e24a 100644
--- a/lib/std/start.zig
+++ b/lib/std/start.zig
@@ -669,6 +669,11 @@ inline fn callMainWithArgs(argc: usize, argv: [*][*:0]u8, envp: [][*:0]u8) u8 {
     std.os.argv = argv[0..argc];
     std.os.environ = envp;
 
+    if (std.io_options.debug_threaded_io) |t| {
+        if (@sizeOf(std.Io.Threaded.Argv0) != 0) t.argv0.value = argv[0];
+        t.environ = .{ .block = envp };
+    }
+
     std.debug.maybeEnableSegfaultHandler();
 
     return callMain();
@@ -691,6 +696,11 @@ fn main(c_argc: c_int, c_argv: [*][*:0]c_char, c_envp: [*:null]?[*:0]c_char) cal
 
 fn mainWithoutEnv(c_argc: c_int, c_argv: [*][*:0]c_char) callconv(.c) c_int {
     std.os.argv = @as([*][*:0]u8, @ptrCast(c_argv))[0..@intCast(c_argc)];
+
+    if (@sizeOf(std.Io.Threaded.Argv0) != 0) {
+        if (std.io_options.debug_threaded_io) |t| t.argv0.value = std.os.argv[0];
+    }
+
     return callMain();
 }