php-src/ext/dba/README
Peter Kokot 1c850bfcca Sync leading and final newlines in source code files
This patch adds missing newlines, trims multiple redundant final
newlines into a single one, and trims redundant leading newlines.

According to POSIX, a line is a sequence of zero or more non-' <newline>'
characters plus a terminating '<newline>' character. [1] Files should
normally have at least one final newline character.

C89 [2] and later standards [3] mention a final newline:
"A source file that is not empty shall end in a new-line character,
which shall not be immediately preceded by a backslash character."

Although it is not mandatory for all files to have a final newline
fixed, a more consistent and homogeneous approach brings less of commit
differences issues and a better development experience in certain text
editors and IDEs.

[1] http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_206
[2] https://port70.net/~nsz/c/c89/c89-draft.html#2.1.1.2
[3] https://port70.net/~nsz/c/c99/n1256.html#5.1.1.2
2018-10-14 12:55:24 +02:00

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These functions build the foundation for accessing Berkeley DB style
databases.
This is a general abstraction layer for several file-based databases. As
such, functionality is limited to a common subset of features supported
by modern databases such as Sleepycat Software's DB2. (This is not to be
confused with IBM's DB2 software, which is supported through the ODBC
functions.)
This extensions allows to work with the following databases:
dbm DBM is the oldest (original) type of Berkeley DB style databases.
You should avoid it, if possible. We do not support the
compatibility functions built into DB2 and gdbm, because they are
only compatible on the source code level, but cannot handle the
original dbm format.
ndbm NDBM is a newer type and more flexible than dbm. It still has
most of the arbitrary limits of dbm (therefore it is deprecated).
gdbm GDBM is the GNU database manager.
db2 DB2 is Sleepycat Software's DB2. It's described as "a programmatic
toolkit that provides high-performance built-in database support
for both standalone and client/server applications.
db3 DB3 is Sleepycat Software's DB3.
db4 DB4 is Sleepycat Software's DB4. This is available since PHP 5.0.
cdb CDB is "a fast, reliable, lightweight package for creating and
reading constant databases." It is from the author of qmail and
can be found at http://cr.yp.to/cdb.html. Since it is constant,
we support only reading operations. And since PHP 4.3.0 we support
writing (not updating) through the internal cdb library.
cdb_make Since PHP 4.3.0 we support creation (not updating) of cdb files
when the bundled cdb library is used.
flatfile This is available since PHP 4.3.0 for compatibility with the
deprecated dbm extension only and should be avoided. However you
may use this where files were created in this format. That happens
when configure could not find any external library.
inifile This is available since PHP 4.3.3 to be able to modify php.ini
files from within PHP scripts. When working with ini files you
can pass arrays of the form array(0=>group,1=>value_name) or
strings of the form "[group]value_name" where group is optional.
As the functions dba_firstkey() and dba_nextkey() return string
representations of the key there is a new function dba_key_split()
available since PHP 5 which allows to convert the string keys into
array keys without losing FALSE.
qdbm This is available since PHP 5.0.0. The qdbm library can be loaded
from http://qdbm.sourceforge.net.
After configuring and compiling PHP you must execute the following test
from commandline:
php run-tests.php ext/dba.
This shows whether your combination of handlers works. Most problematic
are dbm and ndbm which conflict with many installations. The reason for
this is that on several systems these libraries are part of more than one
other library. The configuration test only prevents you from configuring
malfaunctioning single handlers but not combinations.