stpncpy: Allow stpncpy to be defined as a macro.

[gnulib.git] / lib / ftruncate.c

diff --git a/lib/ftruncate.c b/lib/ftruncate.c
index 17d263d..33b69d8 100644 (file)
--- a/lib/ftruncate.c
+++ b/lib/ftruncate.c
@@ -1,30 +1,32 @@
 /* ftruncate emulations that work on some System V's.
-   This file is in the public domain. */
+   This file is in the public domain.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <unistd.h>
 
 #include <sys/types.h>
 #include <fcntl.h>
 
 #ifdef F_CHSIZE
+
 int
-ftruncate (fd, length)
-     int fd;
-     off_t length;
+ftruncate (int fd, off_t length)
 {
   return fcntl (fd, F_CHSIZE, length);
 }
-#else
-#ifdef F_FREESP
-/* The following function was written by
-   kucharsk@Solbourne.com (William Kucharski) */
 
-#include <sys/stat.h>
-#include <errno.h>
-#include <unistd.h>
+#else /* not F_CHSIZE */
+# ifdef F_FREESP
+
+/* By William Kucharski <kucharsk@netcom.com>.  */
+
+#  include <sys/stat.h>
+#  include <errno.h>
 
 int
-ftruncate (fd, length)
-     int fd;
-     off_t length;
+ftruncate (int fd, off_t length)
 {
   struct flock fl;
   struct stat filebuf;
@@ -36,37 +38,53 @@ ftruncate (fd, length)
     {
       /* Extend file length. */
       if (lseek (fd, (length - 1), SEEK_SET) < 0)
-       return -1;
+        return -1;
 
       /* Write a "0" byte. */
       if (write (fd, "", 1) != 1)
-       return -1;
+        return -1;
     }
   else
     {
+
       /* Truncate length. */
+
       fl.l_whence = 0;
       fl.l_len = 0;
       fl.l_start = length;
-      fl.l_type = F_WRLCK;     /* Write lock on file space. */
+      fl.l_type = F_WRLCK;      /* write lock on file space */
+
+      /* This relies on the *undocumented* F_FREESP argument to fcntl,
+         which truncates the file so that it ends at the position
+         indicated by fl.l_start.  Will minor miracles never cease?  */
 
-      /* This relies on the UNDOCUMENTED F_FREESP argument to
-        fcntl, which truncates the file so that it ends at the
-        position indicated by fl.l_start.
-        Will minor miracles never cease? */
       if (fcntl (fd, F_FREESP, &fl) < 0)
-       return -1;
+        return -1;
     }
 
   return 0;
 }
-#else
+
+# else /* not F_CHSIZE nor F_FREESP */
+#  if HAVE_CHSIZE                      /* native Windows, e.g. mingw */
+
 int
-ftruncate (fd, length)
-     int fd;
-     off_t length;
+ftruncate (int fd, off_t length)
 {
   return chsize (fd, length);
 }
-#endif
-#endif
+
+#  else /* not F_CHSIZE nor F_FREESP nor HAVE_CHSIZE */
+
+#   include <errno.h>
+
+int
+ftruncate (int fd, off_t length)
+{
+  errno = EIO;
+  return -1;
+}
+
+#  endif /* not HAVE_CHSIZE */
+# endif /* not F_FREESP */
+#endif /* not F_CHSIZE */