diff --git a/configure.ac b/configure.ac
index 4c3e3cf..abf7462 100644
--- a/configure.ac
+++ b/configure.ac
@@ -38,7 +38,7 @@ AC_SUBST(DLL_LDFLAGS)
 AC_CHECK_HEADERS(windows.h winsock2.h io.h process.h unistd.h inttypes.h stdint.h getopt.h libc.h malloc.h dlfcn.h regex.h sys/cdefs.h sys/socket.h netinet/in.h sys/uio.h aio.h sys/mman.h sys/wait.h sys/resource.h sys/time.h endian.h)
 
 AC_CHECK_FUNCS(setenv waitpid setrlimit gettimeofday fork kill pipe _pipe)
-AC_CHECK_FUNCS(open64 lseek64 mmap64 fopen64 dup dup2 fseeko _IO_getc getline getdelim __getdelim fgetln __srefill map_fd memalign posix_memalign aio_read accept bind connect socket readv pread recv recvfrom recvmsg mmap valloc sigaction getpagesize getc_unlocked getchar_unlocked fgetc_unlocked fread_unlocked fgets_unlocked)
+AC_CHECK_FUNCS(open64 __open64 lseek64 mmap64 fopen64 __fopen64 __freopen64 dup dup2 fseeko __fseeko64 _IO_getc getline getdelim __getdelim fgetln __srefill map_fd memalign posix_memalign aio_read accept bind connect socket readv pread recv recvfrom recvmsg mmap valloc sigaction getpagesize getc_unlocked getchar_unlocked fgetc_unlocked fread_unlocked fgets_unlocked)
 
 AC_CHECK_TYPES(sighandler_t, [], [],
   [#define _GNU_SOURCE
diff --git a/doc/libzzuf.3 b/doc/libzzuf.3
index 3ace926..bc7d725 100644
--- a/doc/libzzuf.3
+++ b/doc/libzzuf.3
@@ -93,18 +93,22 @@ Memory management:
 \fBmmap\fR(), \fBmunmap\fR(), \fBmalloc\fR(), \fBcalloc\fR(), \fBvalloc\fR(),
 \fBfree\fR(), \fBmemalign\fR(), \fBposix_memalign\fR()
 .TP
-Linux-specific:
+Required on Linux:
 \fBopen64\fR(), \fBlseek64\fR(), \fBmmap64\fR(), \fB_IO_getc\fR(),
 \fBgetline\fR(), \fBgetdelim\fR(), \fB__getdelim\fR(), \fBgetc_unlocked\fR(),
 \fBgetchar_unlocked\fR(), \fBfgetc_unlocked\fR(), \fBfgets_unlocked\fR(),
 \fBfread_unlocked\fR()
 .TP
-BSD-specific:
+Required on BSD systems:
 \fBfgetln\fR(), \fB__srefill\fR()
 .TP
-Mac OS X-specific:
+Required on Mac OS X:
 \fBmap_fd\fR()
 .TP
+Required on HP-UX:
+\fB__fopen64\fR(), \fB__fseeko64\fR(), \fB__freopen64\fR(), \fB__open64\fR(),
+\fB__lseek64\fR()
+.TP
 Signal handling:
 \fBsignal\fR(), \fBsigaction\fR()
 .PP
diff --git a/src/lib-fd.c b/src/lib-fd.c
index b990003..35fadba 100644
--- a/src/lib-fd.c
+++ b/src/lib-fd.c
@@ -83,6 +83,9 @@ static int     (*ORIG(open))    (const char *file, int oflag, ...);
 #if defined HAVE_OPEN64
 static int     (*ORIG(open64))  (const char *file, int oflag, ...);
 #endif
+#if defined HAVE___OPEN64
+static int     (*ORIG(__open64))(const char *file, int oflag, ...);
+#endif
 #if defined HAVE_DUP
 static int     (*ORIG(dup))     (int oldfd);
 #endif
@@ -133,6 +136,9 @@ static off_t   (*ORIG(lseek))   (int fd, off_t offset, int whence);
 #if defined HAVE_LSEEK64
 static off64_t (*ORIG(lseek64)) (int fd, off64_t offset, int whence);
 #endif
+#if defined HAVE___LSEEK64
+static off64_t (*ORIG(__lseek64)) (int fd, off64_t offset, int whence);
+#endif
 static int     (*ORIG(close))   (int fd);
 
 #define OPEN(fn) \
@@ -179,6 +185,13 @@ int NEW(open64)(const char *file, int oflag, ...)
 }
 #endif
 
+#if defined HAVE___OPEN64
+int NEW(__open64)(const char *file, int oflag, ...)
+{
+    int ret; OPEN(__open64); return ret;
+}
+#endif
+
 #if defined HAVE_DUP
 int NEW(dup)(int oldfd)
 {
@@ -522,9 +535,14 @@ off_t NEW(lseek)(int fd, off_t offset, int whence)
 #if defined HAVE_LSEEK64
 off64_t NEW(lseek64)(int fd, off64_t offset, int whence)
 {
-    off64_t ret;
-    LSEEK(lseek64, off64_t);
-    return ret;
+    off64_t ret; LSEEK(lseek64, off64_t); return ret;
+}
+#endif
+
+#if defined HAVE___LSEEK64
+off64_t NEW(__lseek64)(int fd, off64_t offset, int whence)
+{
+    off64_t ret; LSEEK(__lseek64, off64_t); return ret;
 }
 #endif
 
diff --git a/src/lib-stream.c b/src/lib-stream.c
index 32200e2..7ffe875 100644
--- a/src/lib-stream.c
+++ b/src/lib-stream.c
@@ -48,12 +48,22 @@ static FILE *  (*ORIG(fopen))    (const char *path, const char *mode);
 #if defined HAVE_FOPEN64
 static FILE *  (*ORIG(fopen64))  (const char *path, const char *mode);
 #endif
+#if defined HAVE___FOPEN64
+static FILE *  (*ORIG(__fopen64))(const char *path, const char *mode);
+#endif
 static FILE *  (*ORIG(freopen))  (const char *path, const char *mode,
                                   FILE *stream);
+#if defined HAVE___FREOPEN64
+static FILE *  (*ORIG(__freopen64)) (const char *path, const char *mode,
+                                     FILE *stream);
+#endif
 static int     (*ORIG(fseek))    (FILE *stream, long offset, int whence);
 #if defined HAVE_FSEEKO
 static int     (*ORIG(fseeko))   (FILE *stream, off_t offset, int whence);
 #endif
+#if defined HAVE___FSEEKO64
+static int     (*ORIG(__fseeko64)) (FILE *stream, off_t offset, int whence);
+#endif
 static void    (*ORIG(rewind))   (FILE *stream);
 static size_t  (*ORIG(fread))    (void *ptr, size_t size, size_t nmemb,
                                   FILE *stream);
@@ -134,36 +144,49 @@ FILE *NEW(fopen64)(const char *path, const char *mode)
 }
 #endif
 
+#if defined HAVE___FOPEN64
+FILE *NEW(__fopen64)(const char *path, const char *mode)
+{
+    FILE *ret; FOPEN(__fopen64); return ret;
+}
+#endif
+
+#define FREOPEN(fn) \
+    do \
+    { \
+        int fd0 = -1, fd1 = -1, disp = 0; \
+        LOADSYM(fn); \
+        if(_zz_ready && (fd0 = fileno(stream)) >= 0 && _zz_iswatched(fd0)) \
+        { \
+            _zz_unregister(fd0); \
+            disp = 1; \
+        } \
+        _zz_lock(-1); \
+        ret = ORIG(fn)(path, mode, stream); \
+        _zz_unlock(-1); \
+        if(ret && _zz_mustwatch(path)) \
+        { \
+            fd1 = fileno(ret); \
+            _zz_register(fd1); \
+            disp = 1; \
+        } \
+        if(disp) \
+            debug("%s(\"%s\", \"%s\", [%i]) = [%i]", __func__, \
+                  path, mode, fd0, fd1); \
+    } while(0)
+
 FILE *NEW(freopen)(const char *path, const char *mode, FILE *stream)
 {
-    FILE *ret;
-    int fd0 = -1, fd1 = -1, disp = 0;
-
-    LOADSYM(freopen);
-    if(_zz_ready && (fd0 = fileno(stream)) >= 0 && _zz_iswatched(fd0))
-    {
-        _zz_unregister(fd0);
-        disp = 1;
-    }
-
-    _zz_lock(-1);
-    ret = ORIG(freopen)(path, mode, stream);
-    _zz_unlock(-1);
-
-    if(ret && _zz_mustwatch(path))
-    {
-        fd1 = fileno(ret);
-        _zz_register(fd1);
-        disp = 1;
-    }
-
-    if(disp)
-        debug("%s(\"%s\", \"%s\", [%i]) = [%i]", __func__,
-              path, mode, fd0, fd1);
-
-    return ret;
+    FILE *ret; FREOPEN(freopen); return ret;
 }
 
+#if defined HAVE___FREOPEN64
+FILE *NEW(__freopen64)(const char *path, const char *mode, FILE *stream)
+{
+    FILE *ret; FREOPEN(__freopen64); return ret;
+}
+#endif
+
 #if defined HAVE___SREFILL /* Don't fuzz or seek if we have __srefill() */
 #   define FSEEK_FUZZ(fn2)
 #else
@@ -214,6 +237,13 @@ int NEW(fseeko)(FILE *stream, off_t offset, int whence)
 }
 #endif
 
+#if defined HAVE___FSEEKO64
+int NEW(__fseeko64)(FILE *stream, off64_t offset, int whence)
+{
+    int ret; FSEEK(__fseeko64, ftello); return ret;
+}
+#endif
+
 void NEW(rewind)(FILE *stream)
 {
     int fd;