Thread: gcc/borland and sscanf format specifiers

Hello,

I guess it was a mistake to trust cygwin gcc 3.2 alone for the last weeks. I've just compiled my application with the Borland Command Line Tools 5.5.x. But this time the command line interface - provided by http://argtable.sourceforge.net/ - wouldn't work correctly.
I checked the argtable library function for parsing the command line and found this:

Code:

/*-- scan an int value --*/
// eliminated space between %i and %n to make it work with borland
      if (sscanf(str,"%i %n",&intval,&length) !=1) 
         return -1;

This first error (str,"%i %n"...) was obvious. I just wonder why GCC 3.2 didn't warn me? Does GCC ignore such spaces in fomat strings or correct such errors quietly or - to make it even worse - not notice them at all? After removing the space the Borland compiled program would work as expected.

But then I found this some lines below:

Code:

/*-- scan for quoted string fist, if no good then try unquoted --*/
      if (sscanf(str," '%[^']'%n",strval,&length) != 1)
     // is the space after str," a problem?

I do not have the experience to tell wether this space at the beginning of the format string is a source of problems. Sadly, I can't find a note on spaces in format strings in the ANSI-C standard. What I remember is my Prof. saying that spaces in format string of scanf and related functions are "deadly".

Any help is really appreciated.

This post makes no sense. All the above code is perfectly legal. Here is a bit more on the topic. Having spaces in your scan strings is also fine. You just have to be aware of what you're looking for. I don't see spaces as "deadly".

In the provided link, pay attention to the "Conversion Speficierrs" section.

Quzah.

[latest edit]
Your right, quzah! I've found the problem. I forgot totally that I had to convert the source files from DOS to UNIX format in order to compile them with GCC. And after about 2 months working with GCC alone, I had totally forgotten to convert the files back to DOS format in order to compile them with Borland without such strange errors.
%%&| happens ...
[/latest edit]

This post makes no sense. All the above code is perfectly legal.

Well, GCC and Borland obviously treat the following source code differently:

Code:

sscanf(str,"%i %n", ......);

Both compile without errors or warnings. With GCC the command line parsing works just as expected but the program compiled with Borland prints out an error message:

Code:

C:\cygwin\home\User>program input.txt -calc1 -print yes -nbr 1500 -color off

-nbr 1500

     ^^^^ unexpected argument

But when I remove the space from the format string, the command line interface suddenly works as it did before with GCC and the space.

[edit]
A possible explanation may be that the command line is processed differently by the cygwin emulated Unix Shell and the Win2000 "DOS"-Box.
Hmmm ... but then why does the GCC compiled program work, too, when started from the "DOS"-Box? When compiled with Borland the program doesn't work from neither cygwin shell nor "DOS"-Box.
I really don't know what's the course of this problem ...
[/edit]