Index: kio/io.h
==================================================================
--- kio/io.h
+++ kio/io.h
@@ -55,13 +55,24 @@
 	 * select explicitly against kiocond_ok or kiocond_partial, since
 	 * those situations will usually need to be handled differently. */
 
 	kiocond_ok, // success
 	kiocond_partial, // partial read or write
+	kiocond_poll, // call would block
+	kiocond_interrupt, // call was interrupted by signal
 
     kiocond_fail, // action failed - unspecified reason
 	kiocond_fail_closed_stream, // action failed because stream is closed
+	kiocond_fail_invalid,
+	kiocond_fail_io,
+	kiocond_fail_no_peer,
+	kiocond_fail_no_space,
+	kiocond_fail_forbidden,
+	kiocond_fail_over_quota,
+	kiocond_fail_pfault,
+	kiocond_fail_too_big,
+	kiocond_fail_stream_mismatch,
 } kiocond;
 
 kiocond kiosend(kiochan, ksraw, sz*); // send data to a channel
 kiocond kiorecv(kiochan, ksraw*); // receive data from a channel
 kmptr kiorecvall(kiochan, kmcell*, kmkind); // automatically allocate a bufer for a channel

Index: kio/send.fn.c
==================================================================
--- kio/send.fn.c
+++ kio/send.fn.c
@@ -9,10 +9,11 @@
 /* we define all platform functions here,
  * whether or not they're for the correct
  * platform - only the ones actually called
  * by the generated code will be linked */
 #include <posix.h>
+#include <error_table.h>
 
 kiocond kiosend(kiochan target, ksraw string, sz* len) {
 	if (target.out.kind == kiostream_closed) return kiocond_fail_closed_stream;
 
 #	ifdef KFenv_posix
@@ -24,11 +25,24 @@
 
 		struct k_platform_syscall_answer a = k_platform_syscall
 			(k_platform_syscall_write,3,args);
 
 		sz size = a.ret;
-		if (size == -1) return kiocond_fail; //TODO: retrieve errno and offer more specific errors
+		if (size == -1) switch(a.error) {
+			case k_platform_error_EPERM:  return kiocond_fail_forbidden;
+			case k_platform_error_EINVAL: return kiocond_fail_invalid;
+			case k_platform_error_EBADF:  return kiocond_fail_invalid;
+			case k_platform_error_EFAULT: return kiocond_fail_pfault;
+			case k_platform_error_ENOSPC: return kiocond_fail_no_space;
+			case k_platform_error_EDQUOT: return kiocond_fail_over_quota;
+			case k_platform_error_EIO:    return kiocond_fail_io;
+			case k_platform_error_EAGAIN: return kiocond_poll;
+			case k_platform_error_EFBIG:  return kiocond_fail_too_big;
+			case k_platform_error_EINTR:  return kiocond_interrupt;
+			case k_platform_error_EDESTADDRREQ: return kiocond_fail_no_peer;
+			default: return kiocond_fail;
+		}
 #	else
 #		if KVos == win
 #			error windows IO send function not yet defined
 #		else
 			Knoimpl(kiosend,KVos);

Index: makefile
==================================================================
--- makefile
+++ makefile
@@ -3,11 +3,11 @@
 # TODO: calculate these using $(MAKE_HOST)
 export ARCH = x86
 export OS = lin
 export BITS = 64
 export ROOT = $(PWD)
-export TMP = $(PWD)/tmp
+export TMP = $(PWD)/gen
 
 ifneq ($(BITS),)
     export TARGET = $(ARCH).$(OS).$(BITS)
 else
     export TARGET = $(ARCH).$(OS)
@@ -92,25 +92,32 @@
 
 lists = moddirs functions assemblies fnobjects rtobjects binaries binmods POSIX
 dbg:
 	@echo -e lists: $(foreach var, $(lists), "\\n - \\e[1m$(var)\\e[m = $($(var))")
 
-%.obj: %/makefile $(TMP)/system_calls.h $(TMP)/system_calls.s $(OUT)
+%.obj: %/makefile  $(OUT)
 	cd $* && $(MAKE) obj
 
 %.tool: %/makefile $(OUT)
 	cd $* && $(MAKE) tool
 
 %.dbg: %/makefile $(OUT)
 	cd $* && $(MAKE) dbg
 
-%.def: %/makefile $(TMP)/typesize.def $(OUT) $(OUT)/k
+%.def: %/makefile $(TMP)/typesize.def \
+                  $(TMP)/system_calls.h \
+				  $(TMP)/system_calls.s \
+				  $(TMP)/error_table.h \
+				  $(OUT) $(OUT)/k
 	cd $* && $(MAKE) def
 
 .PRECIOUS: $(TMP)/system_calls.%
 $(TMP)/system_calls.%: arch/makefile
 	$(MAKE) -C arch $@
+
+$(TMP)/error_table.h: arch/makefile
+	$(MAKE) -C arch $@
 
 $(TMP)/typesize.def: arch/makefile $(TMP)
 	$(MAKE) -C arch $@
 
 $(OUT)/libk.so: $(fnobjects)