🚀 go-pugleaf

In article <92Aug31.092656edt.133099@wotan.ai.toronto.edu> kramer@cs.toronto.edu ("Bryan M. Kramer") writes:
>Is there a stream class (g++ 2.2.2) that supports something
>like popen? I'd like to connect a stream to a pipe.

Yes, almost; that is, there is a class derived from streambuf called
procbuf that does what you want.  Here is an example program.  It takes
two arguments; the first is the name of a file, the second is a command.
The program reads the file and pipes it through the command.  The command
is expanded by /bin/sh, so shell metacharacters work (or must be escaped
if that's not what you want).

Here's the program:

--------------------------------------------------------------------------
#include <procbuf.h>
#include <fstream.h>
#include <iostream.h>

main (int argc, char** argv) {
	if (argc != 3) {
		cerr << "Usage: " << argv[0] << " file 'command'\n";
		return 1;
	}

	// open the file with an ifstream

	ifstream istr(argv[1]);
	if (!istr) {
		cerr << argv[0] << ": Can't open file " << argv[1] << "\n";
		return 1;
	}

	// create a procbuf with the command and attach it to an ostream.
	// we could also have used ios::in and attached to an istream to
	// read from a command.

	procbuf pbuf(argv[2], ios::out);
	ostream ostr(&pbuf);

	// not sure this is the right way to check for failure

	if (!ostr) {
		cerr << argv[0] << ": Can't open pipe to '" << argv[2] << "'\n";
		return 1;
	}

	// copy everything from one stream to the other

	char ch;
	while (istr.get(ch)) ostr.put(ch);
	return 0;
}



--
Joe Buck	jbuck@ohm.berkeley.edu