diff --git a/libc/include/sys/linux-syscalls.h b/libc/include/sys/linux-syscalls.h
index 35729ae..cb4d5e5 100644
--- a/libc/include/sys/linux-syscalls.h
+++ b/libc/include/sys/linux-syscalls.h
@@ -71,6 +71,7 @@
 #define __NR_dup2                         (__NR_SYSCALL_BASE + 63)
 #define __NR__newselect                   (__NR_SYSCALL_BASE + 142)
 #define __NR_ftruncate                    (__NR_SYSCALL_BASE + 93)
+#define __NR_ftruncate64                  (__NR_SYSCALL_BASE + 194)
 #define __NR_fsync                        (__NR_SYSCALL_BASE + 118)
 #define __NR_fdatasync                    (__NR_SYSCALL_BASE + 148)
 #define __NR_fchown32                     (__NR_SYSCALL_BASE + 207)
diff --git a/libc/include/sys/linux-unistd.h b/libc/include/sys/linux-unistd.h
index 4a61724..f706d00 100644
--- a/libc/include/sys/linux-unistd.h
+++ b/libc/include/sys/linux-unistd.h
@@ -52,8 +52,8 @@
 int              acct (const char*  filepath);
 ssize_t          read (int, void*, size_t);
 ssize_t          write (int, const void*, size_t);
-ssize_t          __pread64 (int, void *, size_t, off_t, off_t);
-ssize_t          __pwrite64 (int, void *, size_t, off_t, off_t);
+ssize_t          pread64 (int, void *, size_t, off64_t);
+ssize_t          pwrite64 (int, void *, size_t, off64_t);
 int              __open (const char*, int, mode_t);
 int              __openat (int, const char*, int, mode_t);
 int              close (int);
@@ -83,6 +83,7 @@
 int              dup2 (int, int);
 int              select (int, struct fd_set *, struct fd_set *, struct fd_set *, struct timeval *);
 int              ftruncate (int, off_t);
+int              ftruncate64 (int, off64_t);
 int              getdents (unsigned int, struct dirent *, unsigned int);
 int              fsync (int);
 int              fdatasync (int);
diff --git a/libc/include/unistd.h b/libc/include/unistd.h
index aa236bd..4534fb9 100644
--- a/libc/include/unistd.h
+++ b/libc/include/unistd.h
@@ -145,6 +145,7 @@
 extern int fsync(int);
 extern int fdatasync(int);
 extern int ftruncate(int, off_t);
+extern int ftruncate64(int, off64_t);
 
 extern int pause(void);
 extern unsigned int alarm(unsigned int);