If Then Trouble - expected a ';' before '_printf_'

[kylespitz]

Hi! I'm new (started trying to understand C this morning), and have been trying to modify Perl (the compiler, not a script) to not only output a message when a script fails to run, but also do delete the offending perl script.

This is the bit of the compiler I am trying to change (version 5.8.8.r5) -
Bold is what I changed.

#else
    if (yyparse() || PL_error_count)
        {
        printf("Eulogize about the failed script.\n");
        //Add a function to delete the script here (any tips appreciated)
        if (PL_minus_c) {
            Perl_croak(aTHX_ "%s had compilation errors.\n", PL_origfilename);
        }       
        else {
            Perl_croak(aTHX_ "Execution of %s aborted due to compilation errors.\n",
                       PL_origfilename);
        }
    }

When I compile:

perl.c:2211: warning: statement with no effect
perl.c:2211: error: expected ';' before '_printf_'

Any help would be very much appreciated! Thanks!
-kylespitz

[QWERTYman]

'#' is used as a preprocessor directive. I do not see how you use it here.

[Duthomhas]

It is being used as a preprocessor directive. He just didn't post the #if.
I suspect that printf() has been redefined somewhere.

[kylespitz]

I think that the #else is used as a preprocessor directive for the gcc compiler I'm using (gentoo linux).

regarding printf() being redefined, I have trouble including stdio.h in the includes, I've tried:

#include <stdio> //and then also 
#include <iostream> // though I didn't use them together at the same time 

i eventually had to use
#include </sys/include/stdio.h>
to have that line compile without error.

As a workaround, because printf() has probably been redefined, could I define my own function - i.e. print_this_please() by copying the relevant code from sdtio.h and then defining print_this_please() at the top of my file?

[Zaita]

If you do not have an #ifdef (or #ifndef) related to that #else then it should be removed.

To use printf, you should need to include <cstdio> . Albeit, printf is still a C function. IOStream gives you access to cout that should be used to output to the screen instead.

e.g
cout << "Hello World!" << endl;

[kylespitz]

the #else is defined elsewhere (I have no idea where because the problem is 5000 lines long, but it compiled fine before I added my two lines)

[kylespitz]

also, i tried making my own function name without defining it elsewhere --> aww_shoot_printf() and got an implicit declaration of function error. i think that means that printf() and fprintf() should work right? perhaps it's a syntax error?

[kylespitz]

oddly enough, when trying #include <cstdio> or <stdio> or <iostream>, I got a file not found error every time. any idea what's causing that?

[Zaita]

I'd say that your compiler's include directories are not configured correctly.

What operating system are you running this on?

[kylespitz]

gentoo linux, it's a version of linux where just about everything needs to be configured by hand, so I wouldn't be surprised at all if I screwed something up.

my compiler:
GCC 4.1.2 (Gentoo 4.1.2 p1.0.2)

companion library:
/usr/lib/gcc/i686-pc-linux-gnu/4.1.2/libgcc.a

[Zaita]

Ahhh ok. /sys/include isn't a standard include directory. /usr/include is :)

It maybe that GCC isn't setup to look in /sys/include by default.

[kylespitz]

also i just tried writing a hello world program from a different directory. The compiler couldn't find iostream this way either! it would make sense that the directories are messed up, where should I be able to find iostream.h or any of the other libraries?

[kylespitz]

i found stdio.h!

if I #include <stdio.h> then my compiler finds it just fine.

however, it still doesn't seem to like printf when I compile perl.c
my hello world program worked just fine (after I found stdio.h and fixed the compiler). I:

#include <stdio.h>

int main() {
printf ( "hello world\n" );
return 0;
}

which output hello world just fine. but when i do the same thing with perl.c it doesn't seem to work., i get the same, "expected a ';' before _printf_" error as before.

btw, zaita, thank you so much for your help.

[Zaita]

It sounds like you have GCC (C) installed but not G++ (C++).
try:
g++ --version

[kylespitz]

g++ --version returned the same result as gcc --version. It looks like g++ and gcc are the same compiler (both have the same copyright and library information)

[helios]

Quick question: Is that printf() the only one, or there are more but that's the only one causing an error?

[kylespitz]

that printf is the only on in the if statement:
#
if (yyparse() || PL_error_count)


also, i think i JUST found the problem! thank you all so much for your help!

zaita helped me find the stdio.h file i needed, and I discovered (thanks to Duoas), that printf is defined differently elsewhere - probably in one of the many #includes that are at the top of the file. printf isn't defined in the file itself.

What i discovered was that I needed to use the printf function that perl described. Once I ran a search (i'm using nano to do the edits :) I found a PerlIO_printf function. I tried to use that function earlier, but it needed more arguments than I understood. After parsing the file some more, I found a PerlIO_printf(PerlIO_stdio, MESSAGE) Basically, by passing a PerlIO_stdio function to the PerlIO_printf, I was able to have perl output anything I wanted it to.

[kylespitz]

However, my real goal is to have perl delete a file when it doesn't compile. could I add a delete function using a similar syntax?