This version of
ptx contains a few features which do not exist in
ptx. These extra features are suppressed by using the
-G command line option, unless overridden by other command line
options. Some GNU extensions cannot be recovered by overriding, so the
simple rule is to avoid -G if you care about GNU extensions.
Here are the differences between this program and System V
ptxreads only one file and sends the result to standard output or, if a second file parameter is given on the command, to that file.
Having output parameters not introduced by options is a dangerous
practice which GNU avoids as far as possible. So, for using
portably between GNU and System V, you should always use it with a
single input file, and always expect the result on standard output. You
might also want to automatically configure in a -G option to
ptx calls in products using
ptx, if the configurator finds
that the installed
ptx accepts -G.
ptxare options -b, -f, -g, -i, -o, -r, -t and -w. All other options are GNU extensions and are not repeated in this enumeration. Moreover, some options have a slightly different meaning when GNU extensions are enabled, as explained below.
nroff. It is rather formatted for a dumb terminal.
nroffoutput may still be selected through option -O.
ptxdoes not accept 8-bit characters, a few control characters are rejected, and the tilde ‘~’ is also rejected.
ptxprocesses only the first 200 characters in each line.
ptx, but still, there are some slight disposition glitches this program does not completely reproduce.