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Re: lynx-dev peculiar behavior
From: |
T.E.Dickey |
Subject: |
Re: lynx-dev peculiar behavior |
Date: |
Sat, 10 Jul 1999 09:33:37 -0400 (EDT) |
> Then please try replacing it with another interactive program that can
> be suspended - less, some other editor, even lynx itself. Try several.
> My guess is you'll see similar behaviour.
>
> I have seen something like this in the past with lynx. I think the
> problem lies in the implementation of system().
It's not 100% ncurses (small relief). I tried lynx with Solaris curses and vi,
and get some odd behavior (using a mail link):
+ when I do 'fg', it does come back to vi, but the video attributes
are incorrect (so all of the text is in reverse-video). That
indicates (to me) that Lynx (or Solaris curses) is writing something.
+ quitting from vi, the control/G doesn't cancel the operation
(control/C still kills it, but that's not quite what I'd like).
I can see similar behavior on Linux using nvi (linked with ncurses).
> Larry, what does the system() man page say? Mine says (linux)
>
> system() executes a command specified in string by calling
> /bin/sh -c string, and returns after the command has been
> completed. During execution of the command, SIGCHLD will
> be blocked, and SIGINT and SIGQUIT will be ignored.
>
> Does yours also mention signals, especially SIGCHLD?
SunOS shell 5.6 Generic_105181-14 sun4u sparc SUNW,Ultra-2
Standard I/O Functions system(3S)
NAME
system - issue a shell command
SYNOPSIS
#include <stdlib.h>
int system(const char *string);
DESCRIPTION
The system() function causes the string to be given to the
shell as input, as if the string had been typed as a command
at a terminal. The invoker waits until the shell has com-
pleted, then returns the exit status of the shell in the
format specified by waitpid(2).
If string is a null pointer, system() checks if the shell
exists and is executable. If the shell is available, sys-
tem() returns non-zero; otherwise it returns zero. If the
application is standard-conforming (see standards(5)), sys-
tem() uses /usr/bin/ksh (see ksh(1)); otherwise system()
uses /usr/bin/sh (see sh(1)).
RETURN VALUES
The system() function forks to create a child process that
in turn execs the shell in order to execute string. If the
fork() or exec() fails, system() returns a value of -1 and
sets errno.
ERRORS
The system() function fails if one or more of the following
are true:
EAGAIN The system-imposed limit on the total number of
processes under execution by a single user would
be exceeded.
EINTR system() was interrupted by a signal.
ENOMEM The new process requires more memory than is
available.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
__________________________________
| ATTRIBUTE TYPE| ATTRIBUTE VALUE|
|_______________|_________________|
| MT-Level | Unsafe |
|_______________|_________________|
SunOS 5.6 Last change: 26 Feb 1997 1
Standard I/O Functions system(3S)
SEE ALSO
ksh(1), sh(1), useradd(1M), exec(2), fork(2), setuid(2),
waitpid(2), attributes(5), standards(5)
NOTES
The system() function will fail to execute setuid() or set-
gid() if either the uid or gid of the application's
owner/group is less than 100. (see useradd(1M) and
setuid(2)).
SunOS 5.6 Last change: 26 Feb 1997 2
--
Thomas E. Dickey
address@hidden
http://www.clark.net/pub/dickey
- Re: lynx-dev peculiar behavior with Ctl-z, (continued)
- Re: lynx-dev peculiar behavior, Klaus Weide, 1999/07/10
- Re: lynx-dev peculiar behavior, Klaus Weide, 1999/07/10
- Re: lynx-dev peculiar behavior, Klaus Weide, 1999/07/10
- Re: lynx-dev peculiar behavior, Larry W. Virden, 1999/07/10
- Re: lynx-dev peculiar behavior, T.E.Dickey, 1999/07/10
- Re: lynx-dev peculiar behavior, T.E.Dickey, 1999/07/10
- Re: lynx-dev peculiar behavior,
T.E.Dickey <=
- Re: lynx-dev peculiar behavior, T.E.Dickey, 1999/07/10
- Re: lynx-dev peculiar behavior, Larry W. Virden, 1999/07/10
- Re: lynx-dev peculiar behavior, Larry W. Virden, 1999/07/10
- Re: lynx-dev peculiar behavior, Larry W. Virden, 1999/07/10
- Re: lynx-dev peculiar behavior, Larry W. Virden, 1999/07/10
- Re: lynx-dev peculiar behavior, Larry W. Virden, 1999/07/10