posix: add package

core/sys/posix/sys_uio.odin

@@ -0,0 +1,42 @@
+package posix
+
+import "core:c"
+
+when ODIN_OS == .Darwin {
+	foreign import libc "system:System.framework"
+} else {
+	foreign import libc "system:c"
+}
+
+// sys/uio.h - definitions for vector I/O operations
+
+foreign libc {
+	/*
+	Equivalent to read() but takes a vector of inputs.
+
+	iovcnt can be 0..=IOV_MAX in length.
+
+	[[ More; https://pubs.opengroup.org/onlinepubs/9699919799/functions/readv.html ]]
+	*/
+	readv  :: proc(fildes: FD, iov: [^]iovec, iovcnt: c.int) -> c.ssize_t ---
+
+	/*
+	Equivalent to write() but takes a vector of inputs.
+
+	iovcnt can be 0..=IOV_MAX in length.
+
+	[[ More; https://pubs.opengroup.org/onlinepubs/9699919799/functions/readv.html ]]
+	*/
+	writev :: proc(fildes: FD, iov: [^]iovec, iovcnt: c.int) -> c.ssize_t ---
+}
+
+when ODIN_OS == .Darwin || ODIN_OS == .FreeBSD || ODIN_OS == .NetBSD || ODIN_OS == .OpenBSD {
+
+	iovec :: struct {
+		iov_base: rawptr,   /* [PSX] base address of I/O memory region */
+		iov_len:  c.size_t, /* [PSX] size of the region iov_base points to */
+	}
+
+} else {
+	#panic("posix is unimplemented for the current target")
+}