A/UX® Programmer's Reference

intro(2)
stdin
stdout
stderr
the standard input file
the standard output file
the standard error file
intro(2)
Output streams, with the exception of the standard error stream
stderr, are, by default, buffered if the output refers to a file and
line-buffered if the output refers to a terminal. The standard error
output stream stderr is, by default, unbuffered. When an output
stream is unbuffered, information is queued for writing on the
destination file or terminal as soon as written; when it is buffered,
many characters are saved up and written as a block. When an
output stream is line-buffered, each line of output is queued for
writing on the destination terminal as soon as the line is completed,
that is, as soon as a newline character is written or terminal input
is requested. The setbuf(3S) routines may be used to
change the buffering strategy of the stream.
Filename
Names consisting of 1 to 14 characters may be used to name an
ordinary file, special file, or directory.
These characters may be selected from the set of all character
values excluding \Q (null) and the ASCII code for / (slash).
Note that it is generally unwise to use *, ?, [, or ] as part of
filenames because of the special meaning attached to these characters
by the shell (see sh(I». Although permitted, it is advisable to
avoid the use of unprintable characters in filenames.
Pathname and Path Prefix
A pathname is a null-terminated character string starting with an
optional slash (I), followed by zero or more directory names
separated by slashes, then optionally followed by a filename.
Unless specifically stated otherwise, the null path name is treated
as if it named a nonexistent file.
More precisely, a pathname is a null-terminated character string
constructed as follows:
::=kpath-prefix>l/
: :=1 /
::= / I /
where is a string of 1 to 14 characters other than the ASCII
slash and null, and is a string of 1 to 14 characters
(other than the ASCII slash and null) that names a directory.
February, 1990 13
Revision C