Hydrogenaudio Forums > Using system() to call application with parameters

Neural_Overload

Jun 9 2008, 19:11

I am trying to mute foobar2000 from the command line using system(). I have tried using

CODE

system("\"C:\\Program Files\\Foobar2000\\foobar2000.exe\" \"/command:volume mute\"");

but that does not seem to be working correctly as the command line says

CODE

'C:\Program' is not recognized as an internal or external command,
operable program or batch file.

when my program is run. I have a feeling it's just a syntax error, but because I'm a noob to C++ I can't see it...

Nickoladze

Jun 9 2008, 20:15

you probably need to escape the spaces

2E7AH

Jun 9 2008, 20:22

well first your backslashes looks very messy.

that error only occures when you use quatation marks incorectly.

you should pass something like:

"c:\program files\foobar2000\foobar2000.exe" /command:volume mute

Neural_Overload

Jun 9 2008, 20:38

QUOTE(2E7AH @ Jun 9 2008, 19:22)

well first your backslashes looks very messy.

that error only occures when you use quatation marks incorectly.

you should pass something like:

"c:\program files\foobar2000\foobar2000.exe" /command:volume mute

Do you mean something like?

CODE

system("\"C:\\Program Files\\Foobar2000\\foobar2000.exe\" /command:volume mute");

I tried that and it doesn't work, foobar says:

CODE

Unable to open item for playback (Unsupported file format):
"C:\Documents and Settings\Neural_Overload\My Documents\Visual Studio 2008\Projects\FooControl\FooControl\mute"

2E7AH

Jun 9 2008, 20:49

sorry, man i don't know the C syntax, but the problem is obviously in the quatation marks.
i was trying to show, only how the parse should look like:

"c:\program files\foobar2000\foobar2000.exe" "/command:volume mute"

and not

"c:\program files\foobar2000\foobar2000.exe" /command:volume mute

my mistake

Neural_Overload

Jun 9 2008, 21:27

QUOTE(2E7AH @ Jun 9 2008, 19:49)

sorry, man i don't know the C syntax, but the problem is obviously in the quatation marks.

i was trayng to show, only how the parse should look like:

"c:\program files\foobar2000\foobar2000.exe" "/command:volume mute"

and not

"c:\program files\foobar2000\foobar2000.exe" /command:volume mute

my mistake

CODE

system("c:\program files\foobar2000\foobar2000.exe" "/command:volume mute");

is this working?

You see, I'm pretty sure you have to escape the double quotes and the backslashes in the path. Kinda like this:

CODE

system("\"c:\\program files\\foobar2000\foobar2000.exe\" \"/command:volume mute\"");

Which as I said before, does not work.

2E7AH

Jun 9 2008, 21:44

you are right, the parse should be fine that way, but...

maybe with 8.3 style:

CODE

system("c:\\progra~1\\foobar~1\\foobar~1.exe \"/command:volume mute\"");

Neural_Overload

Jun 9 2008, 22:32

QUOTE(2E7AH @ Jun 9 2008, 20:44)

you are right, the parse should be fine that way, but...

maybe with 8.3 style:

CODE

system("c:\\progra~1\\foobar~1\\foobar~1.exe \"/command:volume mute\"");

It works if I do that, but now I have to figure out how to convert from normal to 8.3

2E7AH

Jun 9 2008, 22:59

i'm glad that finally something worked.

i don't understand what you have to figure out!?
why do you need that?
what are you trying to do?

Neural_Overload

Jun 10 2008, 10:34

QUOTE(2E7AH @ Jun 9 2008, 21:59)

i'm glad that finally something worked.

i don't understand what you have to figure out!?
why do you need that?
what are you trying to do?

I'm trying to make a program similar to this program HERE however I want to expand upon the idea and so I don't want to use hard coded paths for the reason that people might have foobar in directories other than C:\Program Files\Foobar2000

Yirkha

Jun 10 2008, 10:40

Using the CreateProcess API directly won't suffer from this kind of problems.

foosion

Jun 10 2008, 10:55

QUOTE(Yirkha @ Jun 10 2008, 17:40)

Using the CreateProcess API directly won't suffer from this kind of problems.

Neither would ShellExecute or _exec, and the number of their parameters is less intimidating. Decisions, decisions...

Yirkha

Jun 10 2008, 11:33

The problem with exec(2) is that it does never return.

CODE

Each of the  functions  in  the  exec  family  replaces  the
current  process  image  with  a  new process image. The new
image is constructed from a regular, executable file  called
the  new  process image file. This file is either an execut-
able object file or a file of data for an interpreter. There
is  no  return  from a successful call to one of these func-
tions because the calling process image is overlaid  by  the
new process image.

I think you meant _spawn.

(Yes, ShellExecute would work too, I'm just used to use it only for URLs, documents, etc.)

foosion

Jun 10 2008, 11:48

Oops, indeed.

Neural_Overload

Jun 10 2008, 15:35

QUOTE(foosion @ Jun 10 2008, 09:55)

QUOTE(Yirkha @ Jun 10 2008, 17:40)

Using the CreateProcess API directly won't suffer from this kind of problems.

Neither would ShellExecute or _exec, and the number of their parameters is less intimidating. Decisions, decisions...

Well, that was odd. I tried using shellapi.h and it gave me a ton of compile errors. So I googled and came across someone with similar errors. I used windows.h instead of shellapi.h and my program works, but only if I compile it in DEV-C++. Visual Studio gives me the error

CODE

1>.\foobar.cpp(25) : error C2664: 'ShellExecuteW' : cannot convert parameter 2 from 'const char [5]' to 'LPCWSTR'
1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast

Edit: Problem solved, had to switch to a Multi-byte Character Set instead of Unicode
PS. Thanks for all the help guys! I really appreciate it

kode54

Jun 10 2008, 16:14

QUOTE(Neural_Overload @ Jun 10 2008, 14:35)

QUOTE(foosion @ Jun 10 2008, 09:55)

QUOTE(Yirkha @ Jun 10 2008, 17:40)

Using the CreateProcess API directly won't suffer from this kind of problems.

Neither would ShellExecute or _exec, and the number of their parameters is less intimidating. Decisions, decisions...

Well, that was odd. I tried using shellapi.h and it gave me a ton of compile errors. So I googled and came across someone with similar errors. I used windows.h instead of shellapi.h and my program works, but only if I compile it in DEV-C++. Visual Studio gives me the error

CODE

1>.\foobar.cpp(25) : error C2664: 'ShellExecuteW' : cannot convert parameter 2 from 'const char [5]' to 'LPCWSTR'
1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast

Edit: Problem solved, had to switch to a Multi-byte Character Set instead of Unicode
PS. Thanks for all the help guys! I really appreciate it

Actually, you should use the _T macro to convert the string constants to TCHAR. May as well use Unicode.

Neural_Overload

Jun 12 2008, 03:27

QUOTE(kode54 @ Jun 10 2008, 15:14)

Actually, you should use the _T macro to convert the string constants to TCHAR. May as well use Unicode.

Thanks, that works wonderful!