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changeset 28102:4d021e0dcfee

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fcntl: throw error if operation fails and nargout == 0 (bug #57830). * syscalls.cc (Ffcntl): Add nargout to DEFUN macro invocation. Add command calling form to documentation. Rename "err" to "status" in documentation. Document that status variable is -1 if an error is encountered. Based on nargout variable, either throw an error if operation failed, or return status and msg information.
author Rik <rik@octave.org>
date Tue, 18 Feb 2020 16:46:15 -0800
parents 43c2d9c03cc7
children 1cb3c33f97dc
files libinterp/corefcn/syscalls.cc
diffstat 1 files changed, 20 insertions(+), 5 deletions(-) [+]
line wrap: on
line diff
--- a/libinterp/corefcn/syscalls.cc	Tue Feb 18 16:31:02 2020 -0800
+++ b/libinterp/corefcn/syscalls.cc	Tue Feb 18 16:46:15 2020 -0800
@@ -377,9 +377,10 @@
 
 */
 
-DEFMETHODX ("fcntl", Ffcntl, interp, args, ,
+DEFMETHODX ("fcntl", Ffcntl, interp, args, nargout,
             doc: /* -*- texinfo -*-
-@deftypefn {} {[@var{err}, @var{msg}] =} fcntl (@var{fid}, @var{request}, @var{arg})
+@deftypefn  {} {} fcntl (@var{fid}, @var{request}, @var{arg})
+@deftypefnx {} {[@var{status}, @var{msg}] =} fcntl (@var{fid}, @var{request}, @var{arg})
 Change the properties of the open file @var{fid}.
 
 The following values may be passed as @var{request}:
@@ -430,8 +431,8 @@
 @w{@code{O_NONBLOCK}}.
 @end vtable
 
-If successful, @var{err} is 0 and @var{msg} is an empty string.  Otherwise,
-@var{err} is nonzero and @var{msg} contains a system-dependent error
+If successful, @var{status} is 0 and @var{msg} is an empty string.  Otherwise,
+@var{status} is -1 and @var{msg} contains a system-dependent error
 message.
 @seealso{fopen, dup2}
 @end deftypefn */)
@@ -454,11 +455,25 @@
   if (fid < 0)
     error ("fcntl: invalid file id");
 
+  octave_value_list retval;
   std::string msg;
 
   int status = octave::sys::fcntl (fid, req, arg, msg);
 
-  return ovl (status, msg);
+  if (nargout == 0)
+    {
+      if (status < 0)
+        error ("fcntl: operation failed: %s", msg.c_str ());
+    }
+  else
+    {
+      if (status < 0)
+        retval = ovl (-1.0, msg);
+      else
+        retval = ovl (0.0, "");
+    }
+
+  return retval;
 }
 
 DEFMETHODX ("fork", Ffork, interp, args, ,