Index: uspace/lib/posix/stdio.c
===================================================================
--- uspace/lib/posix/stdio.c	(revision 11544f431436ab8a1d0816ded447ddee663a5ded)
+++ uspace/lib/posix/stdio.c	(revision 2a53f7165baaf7867d2c714d76153b28c9028386)
@@ -726,6 +726,6 @@
  * Rename a file or directory.
  *
- * @param old
- * @param new
+ * @param old Old pathname.
+ * @param new New pathname.
  * @return Zero on success, -1 (with errno set) otherwise.
  */
Index: uspace/lib/posix/stdlib.h
===================================================================
--- uspace/lib/posix/stdlib.h	(revision 11544f431436ab8a1d0816ded447ddee663a5ded)
+++ uspace/lib/posix/stdlib.h	(revision 2a53f7165baaf7867d2c714d76153b28c9028386)
@@ -113,5 +113,5 @@
 extern void posix_free(void *ptr);
 
-/* Temporary files */
+/* Temporary Files */
 extern int posix_mkstemp(char *tmpl);
 
Index: uspace/lib/posix/sys/wait.c
===================================================================
--- uspace/lib/posix/sys/wait.c	(revision 11544f431436ab8a1d0816ded447ddee663a5ded)
+++ uspace/lib/posix/sys/wait.c	(revision 2a53f7165baaf7867d2c714d76153b28c9028386)
@@ -67,7 +67,9 @@
 
 /**
+ * Wait for any child process to stop or terminate.
  * 
- * @param stat_ptr
- * @return
+ * @param stat_ptr Location of the final status code of the child process.
+ * @return ID of the child process for which status is reported,
+ *     -1 on signal interrupt, (pid_t)-1 otherwise.
  */
 posix_pid_t posix_wait(int *stat_ptr)
@@ -79,9 +81,13 @@
 
 /**
+ * Wait for a child process to stop or terminate.
  * 
- * @param pid
- * @param stat_ptr
- * @param options
- * @return
+ * @param pid What child process shall the caller wait for. See POSIX manual
+ *     for details.
+ * @param stat_ptr Location of the final status code of the child process.
+ * @param options Constraints of the waiting. See POSIX manual for details.
+ * @return ID of the child process for which status is reported,
+ *     -1 on signal interrupt, 0 if non-blocking wait is requested but there is
+ *     no child process whose status can be reported, (pid_t)-1 otherwise.
  */
 posix_pid_t posix_waitpid(posix_pid_t pid, int *stat_ptr, int options)
Index: uspace/lib/posix/unistd.c
===================================================================
--- uspace/lib/posix/unistd.c	(revision 11544f431436ab8a1d0816ded447ddee663a5ded)
+++ uspace/lib/posix/unistd.c	(revision 2a53f7165baaf7867d2c714d76153b28c9028386)
@@ -186,5 +186,5 @@
  * Close a file.
  *
- * @param fildes
+ * @param fildes File descriptor of the opened file.
  * @return 0 on success, -1 on error.
  */
@@ -223,5 +223,6 @@
  * Requests outstanding data to be written to the underlying storage device.
  *
- * @param fildes
+ * @param fildes File descriptor of the opened file.
+ * @return Zero on success, -1 otherwise.
  */
 int posix_fsync(int fildes)
@@ -230,4 +231,11 @@
 }
 
+/**
+ * Truncate a file to a specified length.
+ *
+ * @param fildes File descriptor of the opened file.
+ * @param length New length of the file.
+ * @return Zero on success, -1 otherwise.
+ */
 int posix_ftruncate(int fildes, posix_off_t length)
 {
@@ -257,4 +265,10 @@
 }
 
+/**
+ * Duplicate an open file descriptor.
+ *
+ * @param fildes File descriptor to be duplicated.
+ * @return On success, new file descriptor for the same file, otherwise -1.
+ */
 int posix_dup(int fildes)
 {
@@ -262,4 +276,12 @@
 }
 
+/**
+ * Duplicate an open file descriptor.
+ * 
+ * @param fildes File descriptor to be duplicated.
+ * @param fildes2 File descriptor to be paired with the same file description
+ *     as is paired fildes.
+ * @return fildes2 on success, -1 otherwise.
+ */
 int posix_dup2(int fildes, int fildes2)
 {
Index: uspace/lib/posix/unistd.h
===================================================================
--- uspace/lib/posix/unistd.h	(revision 11544f431436ab8a1d0816ded447ddee663a5ded)
+++ uspace/lib/posix/unistd.h	(revision 2a53f7165baaf7867d2c714d76153b28c9028386)
@@ -72,14 +72,10 @@
 /* File Manipulation */
 extern int posix_close(int fildes);
-
 extern ssize_t posix_read(int fildes, void *buf, size_t nbyte);
 extern ssize_t posix_write(int fildes, const void *buf, size_t nbyte);
-
 extern int posix_fsync(int fildes);
 extern int posix_ftruncate(int fildes, posix_off_t length);
-
 extern int posix_rmdir(const char *path);
 extern int posix_unlink(const char *path);
-
 extern int posix_dup(int fildes);
 extern int posix_dup2(int fildes, int fildes2);