How to have fgets() return edited line like in shell?

hkluis · 10-13-2006, 10:34 PM

When I'm in a Linux bash shell, pressing the left and right arrow keys can be used to move the cursor on the command line, while the up and down arrow key can recall command history. But if I write a program that reads an input line using gets() as below, pressing those keys just produces the raw escape sequence. Is there a way to have the line edited, like in the shell, before it is returned by fgets()? Is there an alternative function?

Code:

 while (fgets(buf, sizeof(buf), stdin))
        do_command(buf);

I tried first calling noraw() and nocbreak(), but it does make a difference.

Thanks

zx-1 · 10-13-2006, 11:04 PM

Look into GNU Readline.

hkluis · 10-14-2006, 01:07 AM

Thank you. That works and is very simple.

You would think there would be an option in the shell to have all fgets(stdin) automatically inherit this behavior, so that it would not be necessary to modify the apps.

hkluis · 10-14-2006, 01:46 AM

Actually, I came across "rlfe" which is a wrapper for readline. That might just do it.

10-13-2006, 10:34 PM	#1
hkluis Registered User Join Date: Oct 2006 Posts: 3	How to have fgets() return edited line like in shell? When I'm in a Linux bash shell, pressing the left and right arrow keys can be used to move the cursor on the command line, while the up and down arrow key can recall command history. But if I write a program that reads an input line using gets() as below, pressing those keys just produces the raw escape sequence. Is there a way to have the line edited, like in the shell, before it is returned by fgets()? Is there an alternative function? Code: while (fgets(buf, sizeof(buf), stdin)) do_command(buf); I tried first calling noraw() and nocbreak(), but it does make a difference. Thanks
hkluis is offline

10-13-2006, 11:04 PM	#2
zx-1 Registered User Join Date: Oct 2004 Posts: 151	Look into GNU Readline. __________________ System: Debian Sid and FreeBSD 7.0. Both with GCC 4.3. Useful resources: comp.lang.c FAQ \| C++ FQA Lite
zx-1 is offline

10-14-2006, 01:07 AM	#3
hkluis Registered User Join Date: Oct 2006 Posts: 3	Thank you. That works and is very simple. You would think there would be an option in the shell to have all fgets(stdin) automatically inherit this behavior, so that it would not be necessary to modify the apps.
hkluis is offline

10-14-2006, 01:46 AM	#4
hkluis Registered User Join Date: Oct 2006 Posts: 3	Actually, I came across "rlfe" which is a wrapper for readline. That might just do it.
hkluis is offline

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