System calls?

BlitzMax Forums/BlitzMax Beginners Area/System calls?

jondecker76

(Posted 2010) [#1]

I can't find how to do system calls in BMax (I.e. calling a bash script in linux/ batch file in windows for example)

Surely there must be a way, but I haven't been able to locate it in the docs!

Ked	(Posted 2010) [#2]

Just use System_(cmd:String).

jondecker76

(Posted 2010) [#3]

huh - i can't find that in the command reference anywhere, and it doesn't even highlight in the IDE!

Thanks!

Ked	(Posted 2010) [#4]

Yeah, it's undocumented. It's more of a behind-the-scenes function call. You could always use OpenURL also.

plash

(Posted 2010) [#5]

But, OpenURL will do some magic in certain cases, like on Linux:

Method OpenURL( url$ )
	If getenv_("KDE_FULL_DESKTOP")
		system_ "kfmclient exec ~q"+url+"~q"
	ElseIf getenv_("GNOME_DESKTOP_SESSION_ID")
		system_ "gnome-open ~q"+url+"~q"
	EndIf
End Method

The intention for OpenURL is to open files/web pages, not launching programs (even though that is a side effect).
I would recommend using system_() or TProcess (which is actually a pita to use).

Xerra

(Posted 2010) [#6]

I tried this out with :-

' ** System call example to launch external program within a running blitzmax program **

SuperStrict
Local Cmd:String = "C:\Unlock.exe" ' Name of external program to run.
Local S:TStream=OpenFile(Cmd)
If Not S
	Notify("File not found error!") 
Else
	Print "Launching external command..."
	System_(Cmd:String) ' command executes and program suspends until complete.
	Print "Complete."
EndIf 
End

but that doesn't work yet it did when i first tried it but never since. I know it's a cludgy test if file exists line in there but it wont even work without that check now which is odd.

Any ideas? Oh, and a nicer way to check if a file exists would be great too if someone is feeling generous :)

plash

(Posted 2010) [#7]

@Xerra: You can use FileType(path) to test paths. The return values are FILETYPE_FILE (path exists, and it is a file), FILETYPE_DIR (path exists, and it is a directory) and FILETYPE_NONE (path does not exist).

system_() should work as you are using it, if the path exists.
EDIT: Also, you're opening a stream to the path which is never closed. This is probably why the execution doesn't work (the file is opened as read/write, meaning nothing else can access it until the stream is closed).

Xerra

(Posted 2010) [#8]

Oh man - of course. Thanks plash - that would explain perfectly why it didn't work after one try.

Xerra

(Posted 2010) [#9]

' ** System call example to launch external program within a running blitzmax program **

SuperStrict
Local Cmd:String = "C:\Unlock.exe" ' Name of external program to run.
Local S:Byte=FileType(Cmd)
If Not S
	Notify("File not found error!") 
Else
	Print "Launching external command..."
	System_(Cmd:String) ' command executes and program suspends until complete.
	Print "Complete."
EndIf 
End

in other words. Works just fine.