diff --git a/usr/include/unistd.h b/usr/include/unistd.h
index 4df42d6..c7badd8 100644
--- a/usr/include/unistd.h
+++ b/usr/include/unistd.h
@@ -98,7 +98,7 @@
 __extern ssize_t read(int, void *, size_t);
 __extern ssize_t write(int, const void *, size_t);
 __extern ssize_t pread(int, void *, size_t, off_t);
-__extern ssize_t pwrite(int, void *, size_t, off_t);
+__extern ssize_t pwrite(int, const void *, size_t, off_t);
 
 __extern int dup(int);
 __extern int dup2(int, int);