Shell issue

[SARG]

When using shell the first space is used as a separator although there are quotes.

Using this piece of code

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Shell("""c:\temp\toto test.bat""")
Sleep

gives the following message :
'c:\temp\toto' n'est pas reconnu en tant que commande interne ou externe, un programme exécutable ou un fichier de commandes.
is not recognized as an intern command or extern, a executable program or a command file.

Dont' seem to be a normal behaviour as on a command window using "c:\temp\toto test.bat" gives
'"c:\temp\toto test.bat"' n'est pas reconnu en tant que commande interne ou externe, un programme exécutable ou un fichier de commandes. All the line is taken in account. Obviously in this example the 'toto test.bat doesn't exist.

[fxm]

Under French Windows XP SP3, I obtain this other generic error message (same message for the two test cases):
Le chemin d'accès spécifié est introuvable.

Command window (cmd.exe):
Microsoft Windows XP [version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

[djsfantasi]

I am curious...

Do you mean to execute the following?
Shell("""c:\temp\toto\test.bat""")

Otherwise Windows may be looking for a folder named "toto test.bat" (Yes, you can have .'s in a folder name...)

[SARG]

Sorry not to be clear ;-)

It seems that the quotes are not taken in account when using the SHELL command.
The error message shows only 'c:\temp\toto'.

Directly in a command window you get ' "c:\temp\toto test.bat" ' the entire string.
As you can see in the first error message there is no quote.


@fxm are you just using the two lines of code I gave? Tested also under XP SP3.

@djsfantasy it's an example the name has no signification. Just see that the name in the error message is truncated although there are quotes to keep the whole name.

[fxm]

@fxm are you just using the two lines of code I gave? Tested also under XP SP3.

Yes, exactly your two lines of code!

[codeFoil]

fb_Shell passes the string data unmodified to the C library routine system(). On Win32, I think I recall finding that this eventually results in a call to a routine in MSCRT.DLL which uses the current value of the COMSPEC environment variable to build a command line.

We can get an idea of what is happening after the flow of execution passes outside the FreeBASIC runtime by forcing shell to invoke another program.

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'nulcmd.bas 
#Define ALL_PARAMETERS -1
Print  Command(ALL_PARAMETERS )

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'test.bas
SetEnviron "COMSPEC=nulcmd.exe"
Shell("""c:\temp\toto test.bas""" )
Sleep

[dkl]

FB's Shell() uses the CRT's system() (without parsing the command string), and it seems like system(command) just launches "cmd.exe /c <command>". (If you use shell() to run an existing .bat with a "pause" in it, you can see the cmd.exe process and its command line via Process Explorer)

I'm not sure how cmd.exe works exactly (how it handles its command line), but it seems like it will first try the whole quoted command, and if that fails apparently it drops the quotes and re-parses the command, as a fallback mechanism in case the user did something like <cmd.exe /c "echo foo">. As you've seen, that doesn't seem to happen when you type the command into cmd.exe's command prompt though.

C:\>cmd.exe /c "C:\temp\toto test.bat"
Der Befehl "C:\temp\toto" ist entweder falsch geschrieben oder
konnte nicht gefunden werden.

C:\>"C:\temp\toto test.bat"
Der Befehl ""C:\temp\toto test.bat"" ist entweder falsch geschrieben oder
konnte nicht gefunden werden.

and for comparison:

C:\>echo foo
foo

C:\>"echo foo"
Der Befehl ""echo foo"" ist entweder falsch geschrieben oder
konnte nicht gefunden werden.

C:\>cmd.exe /c echo foo
foo

C:\>cmd.exe /c "echo foo"
foo

[codeFoil]

The issue is two fold. First, the CRT is stripping double quotes from the string. Second, cmd.exe handles quotes in a complicated manner.

From the output of Cmd /?

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If /C or /K is specified, then the remainder of the command line after
the switch is processed as a command line, where the following logic is
used to process quote (") characters:

    1.  If all of the following conditions are met, then quote characters
        on the command line are preserved:

        - no /S switch
        - exactly two quote characters
        - no special characters between the two quote characters,
          where special is one of: &<>()@^|
        - there are one or more whitespace characters between the
          the two quote characters
        - the string between the two quote characters is the name
          of an executable file.

    2.  Otherwise, old behavior is to see if the first character is
        a quote character and if so, strip the leading character and
        remove the last quote character on the command line, preserving
        any text after the last quote character.

[SARG]

@fxm
I guess that the 'c:\temp' directory doesn't exist in your PC.

@dkl and codeFoil
Thanks for your explanations.

In fact the goal was to find the right syntax to execute this shell command :

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dim as string fbcexe="c:\freebasic v23\fbcexe",fname="c:\my dir\test.bas":cmdlfbc=""

Shell(""""+fbcexe+""" """+fname+""" -w 1 -g "+cmdlfbc+" >"""+ExePath+"\fbdebug_compil.log""")

The command should be : shell("c:\freebasic v23\fbcexe" "c:\my dir\test.bas" etc)

There may be spaces inside every file name which are causing some issues.
I was not able to find that syntax, always an error message with the dir name truncated after the first space :
'c:\freebasic'

Nota : the excess space characters near parameters or inside quotes have been added when posting.

[fxm]

@fxm
I guess that the 'c:\temp' directory doesn't exist in your PC.

Yes.

[SARG]

This syntax works :

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Shell(""""""+fbcexe+""""+" -w 1 -g "+""""+fname+""""+cmdlfbc+" >"""+ExePath+"\fbdebug_compil.log""")