DEFOPEN(S) UNIX System V DEFOPEN(S)
Name
defopen, defread - reads default entries
Syntax
int defopen(filename)
char *filename;
char *defread(pattern)
char *pattern;
Description
defopen and defread are a pair of routines designed to allow
easy access to default definition files. UNIX is normally
distributed in binary form; the use of default files allows
OEMs or site administrators to customize utility defaults
without having the source code.
defopen opens the default file named by the pathname in
filename. defopen returns null if it is successful in
opening the file, or the fopen failure code (errno) if the
open fails.
defread reads the previously opened file from the beginning
until it encounters a line beginning with pattern. defread
then returns a pointer to the first character in the line
after the initial pattern. If a trailing newline character
is read it is replaced by a null byte.
When all items of interest have been extracted from the
opened file the program may call defopen with the name of
another file to be searched, or it may call defopen with
NULL, which closes the default file without opening another.
Files
The UNIX convention is for a system program xyz to store its
defaults (if any) in the file /etc/default/xyz.
Diagnostics
defopen returns zero on success and nonzero if the open
fails. The return value is the errno value set by fopen(S).
defread returns NULL if a default file is not open, if the
indicated pattern could not be found, or if it encounters
any line in the file greater than the maximum length of 128
characters.
Notes
The return value points to static data, whose contents are
overwritten by each call.
Value Added
defopen and defread are extensions of AT&T System V provided
by the Santa Cruz Operation.
(printed 6/20/89)