fdopen(open(... vs. a plain fopen(.. - (nf)

[johnl at ima.UUCP]

#R:sri-arpa:-217100:ima:20400008:000:880
ima!johnl    Jun 24 14:58:00 1983

As far as I can tell, there are a few situations where you might want to
do an fdopen() call on an open file descriptor.

	1.  When you want to open a pipe, and popen() isn't quite right.

	2.  When, due to some local convention, you have a file passed
	    already open on, say, fd 3 and you want to use that file.

	3.  When you want to open a tty file for read and write, and use
	    separate stdio FILEs for reading and writing (to avoid the
	    flushing and other funniness when you open something "r+".)

	4.  When, under Sys III at least, you want to use open flags such
	    as NOWAIT, you have to do the open yourself and then fdopen.

You don't need fdopen just to do an ioctl() or fstat() call, since the
macro "fileno(iop)" gets you the file number of an open FILE.

John Levine, decvax!yale-co!jrl, ucbvax!cbosgd!ima!johnl,
{research|allegra|floyd|amd70}!ima!johnl