From f49a8c5431509bdcff75522a31c3ef637e504380 Mon Sep 17 00:00:00 2001
From: Meghan Denny <hello@nektro.net>
Date: Sun, 26 Nov 2023 02:15:17 -0800
Subject: [PATCH] std: make c.versionCheck() a comptime-known function

---
 lib/std/c.zig  | 32 ++++++++++++++------------------
 lib/std/os.zig |  8 ++++----
 2 files changed, 18 insertions(+), 22 deletions(-)

diff --git a/lib/std/c.zig b/lib/std/c.zig
index 6b7fac985c..983c38108a 100644
--- a/lib/std/c.zig
+++ b/lib/std/c.zig
@@ -5,29 +5,25 @@ const page_size = std.mem.page_size;
 const iovec = std.os.iovec;
 const iovec_const = std.os.iovec_const;
 
-/// The return type is `type` to force comptime function call execution.
-/// TODO: https://github.com/ziglang/zig/issues/425
 /// If not linking libc, returns struct{pub const ok = false;}
 /// If linking musl libc, returns struct{pub const ok = true;}
 /// If linking gnu libc (glibc), the `ok` value will be true if the target
 /// version is greater than or equal to `glibc_version`.
 /// If linking a libc other than these, returns `false`.
-pub fn versionCheck(comptime glibc_version: std.SemanticVersion) type {
-    return struct {
-        pub const ok = blk: {
-            if (!builtin.link_libc) break :blk false;
-            if (builtin.abi.isMusl()) break :blk true;
-            if (builtin.target.isGnuLibC()) {
-                const ver = builtin.os.version_range.linux.glibc;
-                const order = ver.order(glibc_version);
-                break :blk switch (order) {
-                    .gt, .eq => true,
-                    .lt => false,
-                };
-            } else {
-                break :blk false;
-            }
-        };
+pub inline fn versionCheck(comptime glibc_version: std.SemanticVersion) bool {
+    return comptime blk: {
+        if (!builtin.link_libc) break :blk false;
+        if (builtin.abi.isMusl()) break :blk true;
+        if (builtin.target.isGnuLibC()) {
+            const ver = builtin.os.version_range.linux.glibc;
+            const order = ver.order(glibc_version);
+            break :blk switch (order) {
+                .gt, .eq => true,
+                .lt => false,
+            };
+        } else {
+            break :blk false;
+        }
     };
 }
 
diff --git a/lib/std/os.zig b/lib/std/os.zig
index 8e47605d27..f07f30513e 100644
--- a/lib/std/os.zig
+++ b/lib/std/os.zig
@@ -483,7 +483,7 @@ pub fn getrandom(buffer: []u8) GetRandomError!void {
     if (builtin.os.tag == .linux or builtin.os.tag == .freebsd) {
         var buf = buffer;
         const use_c = builtin.os.tag != .linux or
-            std.c.versionCheck(std.SemanticVersion{ .major = 2, .minor = 25, .patch = 0 }).ok;
+            std.c.versionCheck(std.SemanticVersion{ .major = 2, .minor = 25, .patch = 0 });
 
         while (buf.len != 0) {
             const res = if (use_c) blk: {
@@ -6210,7 +6210,7 @@ pub fn sendfile(
         .linux => sf: {
             // sendfile() first appeared in Linux 2.2, glibc 2.1.
             const call_sf = comptime if (builtin.link_libc)
-                std.c.versionCheck(.{ .major = 2, .minor = 1, .patch = 0 }).ok
+                std.c.versionCheck(.{ .major = 2, .minor = 1, .patch = 0 })
             else
                 builtin.os.version_range.linux.range.max.order(.{ .major = 2, .minor = 2, .patch = 0 }) != .lt;
             if (!call_sf) break :sf;
@@ -6510,7 +6510,7 @@ var has_copy_file_range_syscall = std.atomic.Value(bool).init(true);
 pub fn copy_file_range(fd_in: fd_t, off_in: u64, fd_out: fd_t, off_out: u64, len: usize, flags: u32) CopyFileRangeError!usize {
     if ((comptime builtin.os.isAtLeast(.freebsd, .{ .major = 13, .minor = 0, .patch = 0 }) orelse false) or
         ((comptime builtin.os.isAtLeast(.linux, .{ .major = 4, .minor = 5, .patch = 0 }) orelse false and
-        std.c.versionCheck(.{ .major = 2, .minor = 27, .patch = 0 }).ok) and
+        std.c.versionCheck(.{ .major = 2, .minor = 27, .patch = 0 })) and
         has_copy_file_range_syscall.load(.Monotonic)))
     {
         var off_in_copy = @as(i64, @bitCast(off_in));
@@ -6829,7 +6829,7 @@ pub fn memfd_createZ(name: [*:0]const u8, flags: u32) MemFdCreateError!fd_t {
     switch (builtin.os.tag) {
         .linux => {
             // memfd_create is available only in glibc versions starting with 2.27.
-            const use_c = std.c.versionCheck(.{ .major = 2, .minor = 27, .patch = 0 }).ok;
+            const use_c = std.c.versionCheck(.{ .major = 2, .minor = 27, .patch = 0 });
             const sys = if (use_c) std.c else linux;
             const getErrno = if (use_c) std.c.getErrno else linux.getErrno;
             const rc = sys.memfd_create(name, flags);