diff --git a/include/igloo/io.h b/include/igloo/io.h
index da002fd..3e42e53 100644
--- a/include/igloo/io.h
+++ b/include/igloo/io.h
@@ -105,17 +105,17 @@ typedef enum {
 typedef struct {
     igloo_interface_base_ifdesc_t __base;
 
-    ssize_t (*read)(igloo_INTERFACE_BASIC_ARGS, void *buffer, size_t len);
-    ssize_t (*write)(igloo_INTERFACE_BASIC_ARGS, const void *buffer, size_t len);
-    int (*flush)(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags);
-    int (*sync)(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags);
-    int (*set_blockingmode)(igloo_INTERFACE_BASIC_ARGS, libigloo_io_blockingmode_t mode);
-    libigloo_io_blockingmode_t (*get_blockingmode)(igloo_INTERFACE_BASIC_ARGS);
-    int (*get_fd_for_systemcall)(igloo_INTERFACE_BASIC_ARGS);
+    ssize_t (*read)(igloo_INTERFACE_BASIC_ARGS, void *buffer, size_t len, igloo_error_t *error);
+    ssize_t (*write)(igloo_INTERFACE_BASIC_ARGS, const void *buffer, size_t len, igloo_error_t *error);
+    igloo_error_t (*flush)(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags);
+    igloo_error_t (*sync)(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags);
+    igloo_error_t (*set_blockingmode)(igloo_INTERFACE_BASIC_ARGS, libigloo_io_blockingmode_t mode);
+    igloo_error_t (*get_blockingmode)(igloo_INTERFACE_BASIC_ARGS, libigloo_io_blockingmode_t *mode);
+    igloo_error_t (*get_fd_for_systemcall)(igloo_INTERFACE_BASIC_ARGS, int *fd);
 #ifdef IGLOO_CTC_STDC_HEADERS
-    int (*control)(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags, igloo_io_control_t control, va_list ap);
+    igloo_error_t (*control)(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags, igloo_io_control_t control, va_list ap);
 #else
-    int (*control)(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags, igloo_io_control_t control, ...);
+    igloo_error_t (*control)(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags, igloo_io_control_t control, ...);
 #endif
 } igloo_io_ifdesc_t;
 
@@ -143,7 +143,7 @@ igloo_io_t * igloo_io_new(const igloo_io_ifdesc_t *ifdesc, igloo_ro_t backend_ob
  * Returns:
  *  The actual amount of bytes read.
  */
-ssize_t igloo_io_read(igloo_io_t *io, void *buffer, size_t len);
+ssize_t igloo_io_read(igloo_io_t *io, void *buffer, size_t len, igloo_error_t *error);
 /* Write data to a IO handle.
  * Parameters:
  *  io
@@ -155,7 +155,7 @@ ssize_t igloo_io_read(igloo_io_t *io, void *buffer, size_t len);
  * Returns:
  *  The actual amount of bytes written.
  */
-ssize_t igloo_io_write(igloo_io_t *io, const void *buffer, size_t len);
+ssize_t igloo_io_write(igloo_io_t *io, const void *buffer, size_t len, igloo_error_t *error);
 
 /* Flush internal buffers to the underlying object.
  * This does not guarantee that all data has been written to the physical level
@@ -166,7 +166,7 @@ ssize_t igloo_io_write(igloo_io_t *io, const void *buffer, size_t len);
  *  flags
  *      Flags for this operation.
  */
-int igloo_io_flush(igloo_io_t *io, igloo_io_opflag_t flags);
+igloo_error_t igloo_io_flush(igloo_io_t *io, igloo_io_opflag_t flags);
 /* Sync object with physical state. This is used to get the object into a state
  * that allows passing the underlying object to other software.
  * This may also flush internal buffers.
@@ -176,7 +176,7 @@ int igloo_io_flush(igloo_io_t *io, igloo_io_opflag_t flags);
  *  flags
  *      Flags for this operation.
  */
-int igloo_io_sync(igloo_io_t *io, igloo_io_opflag_t flags);
+igloo_error_t igloo_io_sync(igloo_io_t *io, igloo_io_opflag_t flags);
 
 /* Set and get the blocking state of the object.
  * Parameters:
@@ -185,8 +185,8 @@ int igloo_io_sync(igloo_io_t *io, igloo_io_opflag_t flags);
  *  mode
  *      The new blocking mode.
  */
-int igloo_io_set_blockingmode(igloo_io_t *io, libigloo_io_blockingmode_t mode);
-libigloo_io_blockingmode_t igloo_io_get_blockingmode(igloo_io_t *io);
+igloo_error_t igloo_io_set_blockingmode(igloo_io_t *io, libigloo_io_blockingmode_t mode);
+igloo_error_t igloo_io_get_blockingmode(igloo_io_t *io, libigloo_io_blockingmode_t *mode);
 
 #ifdef IGLOO_CTC_HAVE_SYS_SELECT_H
 /* Those functions act as igloo's replacement for FD_SET(), FD_CLR(), and FD_SET() and
@@ -208,8 +208,8 @@ libigloo_io_blockingmode_t igloo_io_get_blockingmode(igloo_io_t *io);
  *  to avoid this, as finding the correct parameters for igloo_io_sync() might be tricky.
  *  The object MUST NOT be touched between select() and igloo_io_select_isset().
  */
-int igloo_io_select_set(igloo_io_t *io, fd_set *set, int *maxfd, igloo_io_opflag_t flags);
-int igloo_io_select_clear(igloo_io_t *io, fd_set *set);
+igloo_error_t igloo_io_select_set(igloo_io_t *io, fd_set *set, int *maxfd, igloo_io_opflag_t flags);
+igloo_error_t igloo_io_select_clear(igloo_io_t *io, fd_set *set);
 int igloo_io_select_isset(igloo_io_t *io, fd_set *set);
 #endif
 
@@ -230,7 +230,7 @@ int igloo_io_select_isset(igloo_io_t *io, fd_set *set);
  *  poll() the user MUST call igloo_io_sync() with the correct flags. It is RECOMMENDED
  *  to avoid this, as finding the correct parameters for igloo_io_sync() might be tricky.
  */
-int igloo_io_poll_fill(igloo_io_t *io, struct pollfd *fd, short events);
+igloo_error_t igloo_io_poll_fill(igloo_io_t *io, struct pollfd *fd, short events);
 #endif
 
 /* Advanced control interface.
@@ -248,7 +248,7 @@ int igloo_io_poll_fill(igloo_io_t *io, struct pollfd *fd, short events);
  *      Additional parameters if any.
  *      Values are always passed as pointers.
  */
-int igloo_io_control(igloo_io_t *io, igloo_io_opflag_t flags, igloo_io_control_t control, ...);
+igloo_error_t igloo_io_control(igloo_io_t *io, igloo_io_opflag_t flags, igloo_io_control_t control, ...);
 
 #ifdef __cplusplus
 }
diff --git a/src/io.c b/src/io.c
index b65aa35..84c4217 100644
--- a/src/io.c
+++ b/src/io.c
@@ -15,6 +15,7 @@
 
 #include <igloo/ro.h>
 #include <igloo/io.h>
+#include <igloo/error.h>
 #include "private.h"
 
 struct igloo_io_tag {
@@ -58,9 +59,10 @@ igloo_io_t * igloo_io_new(const igloo_io_ifdesc_t *ifdesc, igloo_ro_t backend_ob
 }
 
 
-ssize_t igloo_io_read(igloo_io_t *io, void *buffer, size_t len)
+ssize_t igloo_io_read(igloo_io_t *io, void *buffer, size_t len, igloo_error_t *error)
 {
     ssize_t ret = -1;
+    igloo_error_t error_store;
 
     if (!io || !buffer)
         return -1;
@@ -68,19 +70,23 @@ ssize_t igloo_io_read(igloo_io_t *io, void *buffer, size_t len)
     if (!len)
         return 0;
 
+    if (!error)
+        error = &error_store;
+
     igloo_thread_mutex_lock(&(io->lock));
     io->touched = 1;
 
     if (io->ifdesc->read)
-        ret = io->ifdesc->read(igloo_INTERFACE_BASIC_CALL(io), buffer, len);
+        ret = io->ifdesc->read(igloo_INTERFACE_BASIC_CALL(io), buffer, len, error);
     igloo_thread_mutex_unlock(&(io->lock));
 
     return ret;
 }
 
-ssize_t igloo_io_write(igloo_io_t *io, const void *buffer, size_t len)
+ssize_t igloo_io_write(igloo_io_t *io, const void *buffer, size_t len, igloo_error_t *error)
 {
     ssize_t ret = -1;
+    igloo_error_t error_store;
 
     if (!io || !buffer)
         return -1;
@@ -88,22 +94,25 @@ ssize_t igloo_io_write(igloo_io_t *io, const void *buffer, size_t len)
     if (!len)
         return 0;
 
+    if (!error)
+        error = &error_store;
+
     igloo_thread_mutex_lock(&(io->lock));
     io->touched = 1;
 
     if (io->ifdesc->write)
-        ret = io->ifdesc->write(igloo_INTERFACE_BASIC_CALL(io), buffer, len);
+        ret = io->ifdesc->write(igloo_INTERFACE_BASIC_CALL(io), buffer, len, error);
     igloo_thread_mutex_unlock(&(io->lock));
 
     return ret;
 }
 
-int igloo_io_flush(igloo_io_t *io, igloo_io_opflag_t flags)
+igloo_error_t igloo_io_flush(igloo_io_t *io, igloo_io_opflag_t flags)
 {
-    int ret = -1;
+    igloo_error_t ret = igloo_ERROR_GENERIC;
 
     if (!io)
-        return -1;
+        return igloo_ERROR_FAULT;
 
     igloo_thread_mutex_lock(&(io->lock));
     io->touched = 1;
@@ -115,12 +124,12 @@ int igloo_io_flush(igloo_io_t *io, igloo_io_opflag_t flags)
     return ret;
 }
 
-int igloo_io_sync(igloo_io_t *io, igloo_io_opflag_t flags)
+igloo_error_t igloo_io_sync(igloo_io_t *io, igloo_io_opflag_t flags)
 {
-    int ret;
+    igloo_error_t ret;
 
     if (!io)
-        return -1;
+        return igloo_ERROR_FAULT;
 
     igloo_thread_mutex_lock(&(io->lock));
     if (io->ifdesc->flush)
@@ -128,7 +137,7 @@ int igloo_io_sync(igloo_io_t *io, igloo_io_opflag_t flags)
 
     if (io->ifdesc->sync) {
         ret = io->ifdesc->sync(igloo_INTERFACE_BASIC_CALL(io), flags);
-        if (ret != 0) {
+        if (ret != igloo_ERROR_NONE) {
             igloo_thread_mutex_unlock(&(io->lock));
             return ret;
         }
@@ -140,18 +149,18 @@ int igloo_io_sync(igloo_io_t *io, igloo_io_opflag_t flags)
     }
     igloo_thread_mutex_unlock(&(io->lock));
 
-    return -1;
+    return igloo_ERROR_GENERIC;
 }
 
-int igloo_io_set_blockingmode(igloo_io_t *io, libigloo_io_blockingmode_t mode)
+igloo_error_t igloo_io_set_blockingmode(igloo_io_t *io, libigloo_io_blockingmode_t mode)
 {
-    int ret = -1;
+    igloo_error_t ret = igloo_ERROR_GENERIC;
 
     if (!io)
-        return -1;
+        return igloo_ERROR_FAULT;
 
     if (mode != igloo_IO_BLOCKINGMODE_NONE && mode != igloo_IO_BLOCKINGMODE_FULL)
-        return -1;
+        return igloo_ERROR_INVAL;
 
     igloo_thread_mutex_lock(&(io->lock));
     io->touched = 1;
@@ -162,52 +171,60 @@ int igloo_io_set_blockingmode(igloo_io_t *io, libigloo_io_blockingmode_t mode)
 
     return ret;
 }
-libigloo_io_blockingmode_t igloo_io_get_blockingmode(igloo_io_t *io)
+igloo_error_t igloo_io_get_blockingmode(igloo_io_t *io, libigloo_io_blockingmode_t *mode)
 {
     libigloo_io_blockingmode_t ret = igloo_IO_BLOCKINGMODE_ERROR;
+    igloo_error_t error = igloo_ERROR_GENERIC;
 
-    if (!io)
-        return igloo_IO_BLOCKINGMODE_ERROR;
+    if (!io || !mode)
+        return igloo_ERROR_FAULT;
 
     igloo_thread_mutex_lock(&(io->lock));
     if (io->ifdesc->get_blockingmode)
-        ret = io->ifdesc->get_blockingmode(igloo_INTERFACE_BASIC_CALL(io));
+        error = io->ifdesc->get_blockingmode(igloo_INTERFACE_BASIC_CALL(io), &ret);
     igloo_thread_mutex_unlock(&(io->lock));
 
-    return ret;
+    if (error != igloo_ERROR_NONE)
+        return error;
+
+    *mode = ret;
+
+    return igloo_ERROR_NONE;
 }
 
 #ifdef IGLOO_CTC_HAVE_SYS_SELECT_H
-int igloo_io_select_set(igloo_io_t *io, fd_set *set, int *maxfd, igloo_io_opflag_t flags)
+igloo_error_t igloo_io_select_set(igloo_io_t *io, fd_set *set, int *maxfd, igloo_io_opflag_t flags)
 {
-    int ret;
+    igloo_error_t ret;
 
     if (!io || !set || !maxfd)
-        return -1;
+        return igloo_ERROR_FAULT;
 
     igloo_thread_mutex_lock(&(io->lock));
     if (!io->ifdesc->get_fd_for_systemcall) {
         igloo_thread_mutex_unlock(&(io->lock));
-        return -1;
+        return igloo_ERROR_GENERIC;
     }
 
     if (io->touched || !(flags & igloo_IO_OPFLAG_NOWRITE)) {
         igloo_thread_mutex_unlock(&(io->lock));
         ret = igloo_io_sync(io, igloo_IO_OPFLAG_DEFAULTS|(flags & igloo_IO_OPFLAG_NOWRITE));
 
-        if (ret != 0)
+        if (ret != igloo_ERROR_NONE)
             return ret;
 
         igloo_thread_mutex_lock(&(io->lock));
         if (io->touched) {
             igloo_thread_mutex_unlock(&(io->lock));
-            return -1;
+            return igloo_ERROR_GENERIC;
         }
     }
 
-    io->fd = io->ifdesc->get_fd_for_systemcall(igloo_INTERFACE_BASIC_CALL(io));
+    ret = io->ifdesc->get_fd_for_systemcall(igloo_INTERFACE_BASIC_CALL(io), &(io->fd));
+    if (ret != igloo_ERROR_NONE)
+        return ret;
     if (io->fd < 0)
-        return -1;
+        return igloo_ERROR_GENERIC;
 
     FD_SET(io->fd, set);
     if (*maxfd < io->fd)
@@ -215,24 +232,24 @@ int igloo_io_select_set(igloo_io_t *io, fd_set *set, int *maxfd, igloo_io_opflag
 
     igloo_thread_mutex_unlock(&(io->lock));
 
-    return 0;
+    return igloo_ERROR_NONE;
 }
 
-int igloo_io_select_clear(igloo_io_t *io, fd_set *set)
+igloo_error_t igloo_io_select_clear(igloo_io_t *io, fd_set *set)
 {
     if (!io || !set)
-        return -1;
+        return igloo_ERROR_FAULT;
 
     igloo_thread_mutex_lock(&(io->lock));
     if (io->touched || io->fd < 0) {
         igloo_thread_mutex_unlock(&(io->lock));
-        return -1;
+        return igloo_ERROR_GENERIC;
     }
 
     FD_CLR(io->fd, set);
     igloo_thread_mutex_unlock(&(io->lock));
 
-    return 0;
+    return igloo_ERROR_GENERIC;
 }
 
 int igloo_io_select_isset(igloo_io_t *io, fd_set *set)
@@ -252,7 +269,7 @@ int igloo_io_select_isset(igloo_io_t *io, fd_set *set)
 #endif
 
 #ifdef IGLOO_CTC_HAVE_POLL
-int igloo_io_poll_fill(igloo_io_t *io, struct pollfd *fd, short events)
+igloo_error_t igloo_io_poll_fill(igloo_io_t *io, struct pollfd *fd, short events)
 {
     static const short safe_events = POLLIN|POLLPRI
 #ifdef POLLRDHUP
@@ -266,14 +283,14 @@ int igloo_io_poll_fill(igloo_io_t *io, struct pollfd *fd, short events)
     int ret;
 
     if (!io || !fd)
-        return -1;
+        return igloo_ERROR_FAULT;
 
     is_safe = !((events|safe_events) - safe_events);
 
     igloo_thread_mutex_lock(&(io->lock));
     if (!io->ifdesc->get_fd_for_systemcall) {
         igloo_thread_mutex_unlock(&(io->lock));
-        return -1;
+        return igloo_ERROR_GENERIC;
     }
 
     if (io->touched || !is_safe) {
@@ -286,14 +303,17 @@ int igloo_io_poll_fill(igloo_io_t *io, struct pollfd *fd, short events)
         igloo_thread_mutex_lock(&(io->lock));
         if (io->touched) {
             igloo_thread_mutex_unlock(&(io->lock));
-            return -1;
+            return igloo_ERROR_GENERIC;
         }
     }
 
-    io->fd = io->ifdesc->get_fd_for_systemcall(igloo_INTERFACE_BASIC_CALL(io));
+    ret = io->ifdesc->get_fd_for_systemcall(igloo_INTERFACE_BASIC_CALL(io), &(io->fd));
     if (io->fd < 0) {
+        ret = igloo_ERROR_GENERIC;
+    }
+    if (ret != igloo_ERROR_NONE) {
         igloo_thread_mutex_unlock(&(io->lock));
-        return -1;
+        return igloo_ERROR_GENERIC;
     }
 
     memset(fd, 0, sizeof(*fd));
@@ -306,14 +326,14 @@ int igloo_io_poll_fill(igloo_io_t *io, struct pollfd *fd, short events)
 }
 #endif
 
-int igloo_io_control(igloo_io_t *io, igloo_io_opflag_t flags, igloo_io_control_t control, ...)
+igloo_error_t igloo_io_control(igloo_io_t *io, igloo_io_opflag_t flags, igloo_io_control_t control, ...)
 {
 #ifdef IGLOO_CTC_STDC_HEADERS
-    int ret = -1;
+    igloo_error_t ret = igloo_ERROR_GENERIC;
     va_list ap;
 
     if (!io)
-        return -1;
+        return igloo_ERROR_FAULT;
 
     igloo_thread_mutex_lock(&(io->lock));
     if (io->ifdesc->control) {
@@ -325,6 +345,6 @@ int igloo_io_control(igloo_io_t *io, igloo_io_opflag_t flags, igloo_io_control_t
 
     return ret;
 #else
-    return -1;
+    return igloo_ERROR_GENERIC;
 #endif
 }
diff --git a/src/logmsg.c b/src/logmsg.c
index 9588071..2ae6669 100644
--- a/src/logmsg.c
+++ b/src/logmsg.c
@@ -227,7 +227,7 @@ static igloo_filter_result_t __handle(igloo_INTERFACE_BASIC_ARGS, igloo_ro_t obj
         break;
     }
 
-    igloo_io_write(igloo_RO_TO_TYPE(*backend_object, igloo_io_t), pre, strlen(pre));
+    igloo_io_write(igloo_RO_TO_TYPE(*backend_object, igloo_io_t), pre, strlen(pre), NULL);
 
     return igloo_FILTER_RESULT_PASS;
 }
@@ -239,7 +239,7 @@ static int __flush(igloo_INTERFACE_BASIC_ARGS)
     if (!io)
         return 0;
 
-    return igloo_io_flush(io, igloo_IO_OPFLAG_DEFAULTS|igloo_IO_OPFLAG_FULL);
+    return igloo_io_flush(io, igloo_IO_OPFLAG_DEFAULTS|igloo_IO_OPFLAG_FULL) == igloo_ERROR_NONE ? 0 : -1;
 }
 
 static int __set_backend(igloo_INTERFACE_BASIC_ARGS, igloo_ro_t backend)
diff --git a/src/stdio.c b/src/stdio.c
index c62fc0a..5e9ab9f 100644
--- a/src/stdio.c
+++ b/src/stdio.c
@@ -13,6 +13,7 @@
 #include <stdio.h>
 
 #include <igloo/io.h>
+#include <igloo/error.h>
 
 static int __free(igloo_INTERFACE_BASIC_ARGS)
 {
@@ -22,30 +23,48 @@ static int __free(igloo_INTERFACE_BASIC_ARGS)
 }
 
 
-static ssize_t __read(igloo_INTERFACE_BASIC_ARGS, void *buffer, size_t len)
+static ssize_t __read(igloo_INTERFACE_BASIC_ARGS, void *buffer, size_t len, igloo_error_t *error)
 {
-    return fread(buffer, 1, len, *backend_userdata);
+    ssize_t ret = fread(buffer, 1, len, *backend_userdata);
+
+    if (ret < 0) {
+        *error = igloo_ERROR_IO;
+    } else {
+        *error = igloo_ERROR_NONE;
+    }
+
+    return ret;
 }
-static ssize_t __write(igloo_INTERFACE_BASIC_ARGS, const void *buffer, size_t len)
+static ssize_t __write(igloo_INTERFACE_BASIC_ARGS, const void *buffer, size_t len, igloo_error_t *error)
 {
-    return fwrite(buffer, 1, len, *backend_userdata);
+    ssize_t ret = fwrite(buffer, 1, len, *backend_userdata);
+
+    if (ret < 0) {
+        *error = igloo_ERROR_IO;
+    } else {
+        *error = igloo_ERROR_NONE;
+    }
+
+    return ret;
 }
 
-static int __flush(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags)
+static igloo_error_t __flush(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags)
 {
-    return fflush(*backend_userdata) == 0 ? 0 : -1;
+    return fflush(*backend_userdata) == 0 ? igloo_ERROR_NONE : igloo_ERROR_GENERIC;
 }
-static int __sync(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags)
+static igloo_error_t __sync(igloo_INTERFACE_BASIC_ARGS, igloo_io_opflag_t flags)
 {
-    return 0;
+    return igloo_ERROR_NONE;
 }
-static libigloo_io_blockingmode_t __get_blockingmode(igloo_INTERFACE_BASIC_ARGS)
+static igloo_error_t __get_blockingmode(igloo_INTERFACE_BASIC_ARGS, libigloo_io_blockingmode_t *mode)
 {
-    return igloo_IO_BLOCKINGMODE_FULL;
+    *mode = igloo_IO_BLOCKINGMODE_FULL;
+    return igloo_ERROR_NONE;
 }
-static int __get_fd_for_systemcall(igloo_INTERFACE_BASIC_ARGS)
+static igloo_error_t __get_fd_for_systemcall(igloo_INTERFACE_BASIC_ARGS, int *fd)
 {
-    return fileno(*backend_userdata);
+    *fd = fileno(*backend_userdata);
+    return igloo_ERROR_NONE;
 }
 
 static const igloo_io_ifdesc_t igloo_stdio_ifdesc = {