command line program in need of error message popup

lra wrote:
> I have a C/C++ program that I've ported from Windows to Mac OS X 10.4. It is
> built using a traditional makefile and g++. While in development, I'm just
> running it from a command line in Terminal. When released, it will just run
> in the background.
>
> The problem I have is this: in order to notify the user of error conditions,
> I used MessageBox() in Windows, which pops up a window with the error message
> text in it and an "OK" button. Is there an analogous function in MacOS,
> without having to build some kind of Carbon/Cocoa application? I saw some
> mention of Alert()/StandardAlert(), but the way I understand it, those are
> used are part of Carbon. I also would like to avoid using Xcode (for
> portability reasons).
>
> Any advice would be well appreciated (please keep in mind that I've only been
> digging through this Mac stuff for about a week now, so my terminology may
> not be accurate).
>

How about using Growl ?

<http://growl.info/about.php>

Paul
 >> Stay informed about: command line program in need of error message popup 

"lra" wrote:

> I have a C/C++ program that I've ported from Windows to Mac OS X 10.4. It is
> built using a traditional makefile and g++. While in development, I'm just
> running it from a command line in Terminal. When released, it will just run
> in the background.

This aritcle may be of interest to you:

<http://developer.apple.com/technotes/tn2005/tn2083.html>

It sounds like you are making an 'agent' type of program.

> The problem I have is this: in order to notify the user of error conditions,
> I used MessageBox() in Windows, which pops up a window with the error message
> text in it and an "OK" button. Is there an analogous function in MacOS,
> without having to build some kind of Carbon/Cocoa application? I saw some
> mention of Alert()/StandardAlert(), but the way I understand it, those are
> used are part of Carbon.

If you want to display a GUI you'll have to link to a framework that
makes that happen (I guess this will be true on Windows too). Either
Cocoa or Carbon can do this. There is nothing special about
'Carbon/Cocoa applications'; a command line tool can link to Cocoa or
Carbon. You don't need to make a bundled app with an icon to use Cocoa
or Carbon.

Minimal Cocoa app:

main.m
------
// to compile: cc main.m -o hello -framework Cocoa

#import <Cocoa/Cocoa.h>
int main (int argc, char *argv[]) { NSLog(@"Hello world"); return 0; }

Adding alerts to your command line app will require only a few lines of
code + linking to Carbon or Cocoa, whichever you prefer (but Carbon may
be a closer fit with your C/C++ code base).

> I also would like to avoid using Xcode (for portability reasons).

Xcode is not a requirement for creating Mac programs (everyting Xcode
does can equally be done from the command line, although it can be a lot
of work...). In other words: Xcode adds no 'magic' ingredients to your
apps.

Hope this helps.

patrick
 >> Stay informed about: command line program in need of error message popup 

"lra via MacKB.com" wrote:

> Here's essentially what I want to do:
>
> Given a "C" code fragment, such as:
> ...
> if (stat("/path/to/file", &statstruct))
> {
> SomeFunction("Can't stat() file: /path/to/file");
> /* clean-up code */
> exit(1);
> }
> ...
>
> What I need to know is what code I should replace "SomeFunction()" with to
> display a (modal) message box that will alert the user to the fatal error.

I'd forgotten about it, but Tom's suggestion of using CFUserNotification
is probably most suited. I imagine you could end up with code like this
(untested!)

// crossplatform.c

#ifdef __APPLE__
// also add linker flag: '-framework CoreFoundation'
#include <CoreFoundation/CoreFoundation.h>
#endif

void DisplayWarning(const char *title, const char *message)
{
#ifdef __APPLE__
// create CFStrings
CFStringRef titleStr = CFStringCreateWithCString(NULL, title,
kCFStringEncodingUTF8);
CFStringRef messageStr = CFStringCreateWithCString(NULL, message,
kCFStringEncodingUTF8);

// present warning
CFUserNotificationDisplayNotice (
0, // no timeout
kCFUserNotificationCautionAlertLevel,
NULL,
NULL,
NULL,
titleStr,
messageStr,
CFSTR("OK)
);

// clean up allocated memory
CFRelease(titleStr);
CFRelease(messageStr);
#else
// your Windows code with equal semantics
#endif
}

patrick
 >> Stay informed about: command line program in need of error message popup 

In article , "lra" wrote:

> I have a C/C++ program that I've ported from Windows to Mac OS X 10.4. It is
> built using a traditional makefile and g++. While in development, I'm just
> running it from a command line in Terminal. When released, it will just run
> in the background.
>
> The problem I have is this: in order to notify the user of error conditions,
> I used MessageBox() in Windows, which pops up a window with the error message
> text in it and an "OK" button. Is there an analogous function in MacOS,
> without having to build some kind of Carbon/Cocoa application?

[lots of useful replies snipped for the sake of conciseness]

In article , "lra via MacKB.com"
clarified:

> I've done a lot of reading, but I'm still unsure how
> to proceed. Here's essentially what I want to do:
>
> Given a "C" code fragment, such as:
> ...
> if (stat("/path/to/file", &statstruct))
> {
> SomeFunction("Can't stat() file: /path/to/file");
> /* clean-up code */
> exit(1);
> }
> ...
>
> What I need to know is what code I should replace "SomeFunction()" with to
> display a (modal) message box that will alert the user to the fatal error.

If you (eventually) want to release a real Mac program, I suggest you
consider the following approach:

- replace
SomeFunction("Can't stat() file: /path/to/file");
by
fprintf( stderr, "Can't stat() file: /path/to/file");
(or the equivalent std::cerr << "...")

- wrap your command-line program in a 'real' Mac program

- have that Mac program call your command-line tool
(see
<http://www.cocoadev.com/index.pl?CocoaWrapperAroundConsoleApplication>)

This will clearly separate the platform-specific stuff from a (possibly
100% platform-independent) core. From the Mac program, it should be
simple to pop up a notification whenever something is written to
standard error.

If you go for a Mac program, also read up on the culture. "Can't stat()
file: /path/to/file" is not a good error message on the Mac, for several
reasons:

- error messages should be more polite ("I am sorry, but I could not...")
- error messages should be less technical (what is 'stat'? I know, but
Mac users will not)
- Mac users may not be that familiar with path separators

(see for example
<http://developer.apple.com/documentation/UserExperience/Conceptual/OSXHI
Guidelines/XHIGWindows/chapter_18_section_7.html#//apple_ref/doc/uid/2000
0961-TPXREF23>)

Reinder
 >> Stay informed about: command line program in need of error message popup