[Octave-bug-tracker] [bug #42549] return code of mkoctfile

[Andreas Weber]

URL:
  <http://savannah.gnu.org/bugs/?42549>

                 Summary: return code of mkoctfile
                 Project: GNU Octave
            Submitted by: andy1978
            Submitted on: Fri 13 Jun 2014 09:24:16 AM GMT
                Category: Libraries
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Regression
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: GNU/Linux

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Details:

See also this thead:
http://octave.1599824.n4.nabble.com/mkoctfile-exits-with-0-if-gcc-failed-td4664462.html
and
http://octave.1599824.n4.nabble.com/RE-return-code-of-mkoctfile-td4664466.html

mkoctfile returns 0 if the called subprocess returns != 0.

~/src/octave-src$ LC_ALL=C mkoctfile nonexistentfile.cpp
g++: error: nonexistentfile.cpp: No such file or directory
g++: fatal error: no input files
compilation terminated.
g++: error: nonexistentfile.o: No such file or directory
~/src/octave-src$ echo $?
0


This is because system returns the exit status of the called process in the
upper 8bits. According to "man wait" WIFEXITED and WEXITSTSTUS should be used
for the bit shifting and masking stuff.

I propose the following patch (hg changeset attached):

diff -r 0ede4dbb37f1 src/mkoctfile.in.cc
--- a/src/mkoctfile.in.cc       Sun Mar 30 14:18:43 2014 -0700
+++ b/src/mkoctfile.in.cc       Wed Jun 04 14:42:58 2014 +0200
@@ -344,7 +344,10 @@
 {
   if (debug)
     std::cout << cmd << std::endl;
-  return system (cmd.c_str ());
+  int result = system (cmd.c_str ());
+  if (WIFEXITED (result))
+    result = WEXITSTATUS (result);
+  return result;
 }

If I use the makros WIFEXITED and WEXITSTATUS I get these warnings when
compiling mkoctfile on debian wheezy 64bit with gcc 4.7.2:

mkoctfile.cc: In function ‘int run_command(const string&)’:
mkoctfile.cc:348:7: warning: use of old-style cast [-Wold-style-cast]
mkoctfile.cc:349:14: warning: use of old-style cast [-Wold-style-cast]


The old style cast is defined in /usr/include/stdlib.h:55

#ifdef __USE_BSD
...
#define __WAIT_INT(status)      (*(int *) &(status))


Perhaps we should use the octave wrappers like in toplev.cc:

if (octave_wait::ifexited (cmd_status))
  cmd_status = octave_wait::exitstatus (cmd_status);
else
  cmd_status = 127;


There are also some other definitions of these makros which wouldn't trigger
teh old-style warning:

$ grep -R "define WEXITSTATUS"
liboctave/system/syswait.h:#define WEXITSTATUS(stat_val) ((unsigned)(stat_val)
>> 8)
configure:# define WEXITSTATUS(stat_val) ((unsigned int) (stat_val) >> 8)
gnulib-hg/lib/sys_wait.in.h:#  define WEXITSTATUS(x) (((x) >> 8) & 0xff)

$ grep -R "define WIFEXITED"
liboctave/system/syswait.h:#define WIFEXITED(stat_val) (((stat_val) & 255) ==
0)
configure:# define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
gnulib-hg/lib/sys_wait.in.h:#  define WIFEXITED(x) (WTERMSIG (x) == 0)
gnulib-hg/lib/sys_wait.in.h:# define WIFEXITED(x) ((x) != 3)


I'll attach a patch using WIFEXITED and WEXITSTATUS (ignoring the old-style
cast warning)

-- Andy 




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