Problem with pipes in C++

[dulesmc]

Hi all,

I'm currently making some very cool archiving library. If you want to see the details about it , you'll find usefull info here , but that's irrelevant for this thread.

I'm currenlty having problems with RAR format.
Since I could not find some decent low-level RAR library, I've decided to use unrar command in background ,and to pipe it trough . I did not simply called fork/exec without pipes, because I want to place progress monitors and appropriate events.

/* This code is bit simplified, of course, I've omitted logging and stuff */


// This command prints given archive-file  to stdout  ( option p   )  
// without printing any extra info like Copyright form RARLabs  ( -inul ) 
// The objective is to have same effect as writing the following in console: 
//  rar p -inul 'myarchive.rar'  'myfile.pdf' >   '/home/dule/myfolder/myfile.pdf' 

FILE *fpipe;
string command= "rar p -inul  \'"  + "myarchive.rar" + "\' \'" + "myfile.pdf" + "\'";

if ( !(fpipe = (FILE*)popen(command.c_str(),"r")) )
{  // If fpipe is NULL
	
	pclose(fpipe);
	exit(1);

}
char c;
ofstream fout( "/home/dule/myfolder/myfile.pdf" );

while( (c = fgetc(fpipe)) != EOF)
{
	fout << c;
}


pclose(fpipe);
return true;

For small text files it works . When I try to do this with , for example , PDF file, program exits cleanly, but it unpacks small portion of file.

When I issue the the following command from shell :
rar p -inul 'myarchive.rar' 'myfile.pdf' > '/home/dule/myfolder/myfile.pdf'

, it works just as it should be.


Thanks in advance.
If anyone needs full source, I'll drop a link

[wje_lf]

You're dealing with binary data here, and there's no guarantee you won't come across weird characters such as hex FF. In fact, hex FF will appear as the EOF indication.

Use fread() instead of fgetc().

Hope this helps.