Pseudo terminals are very convenient for testing purposes, but they are
not fully compatible with real serial (or even usb-serial) hardware.
With the new option, some workarounds can be enabled to hide the
differences and increase compatibility. Although these workarounds
shouldn't cause any problems in production builds, the advise is to
disable this feature.
A few ioctl's are not supported for pseudo terminals. They fail with
EINVAL (Linux) or ENOTTY (Mac OS X). Since these specific error codes
should not occur under normal conditions, they are simply ignored when
pseudo terminal support is enabled.
The TIOCEXCL ioctl (exclusive access) is also problematic. The TIOCEXCL
setting is shared between the master and slave side of the pty. When the
setting is applied on the slave side, it persists for as long as the
master side remains open. The result is that re-opening the slave side
will fail with EBUSY, unless the process has root priviliges. Since this
is very inconvenient, the TIOCEXCL setting is not used when pseudo
terminal support is enabled.
With the new option, the library can be compiled with the entire
logging infrastructure disabled. The public api remains unchanged, but
the internal logging functions will have no effect anymore.
In practice the overhead of the logging functions should be quite
small, and disabling the logging at runtime might be more convenient.
Especially because troubleshooting will become much harder without any
logging.
The new convenience function provides a centralized and threadsafe
function for logging system errors. The previous functions are
deprecated and will be removed after the transition to the new context
based logging.
Since automake 1.12, the warnings in the category 'extra-portability'
are now enabled by '-Wall'. Because of this change, linking libtool
archives requires the new AM_PROG_AR macro.
The public header files are moved to a new subdirectory, to separate
the definition of the public interface from the actual implementation.
Using an identical directory layout as the final installation has the
advantage that the example code can be build outside the project tree
without any modifications to the #include statements.
For development snapshots, a 'devel' suffix is added to distinguish from
the final release. If necessary, the suffix can also be used for 'alpha'
and 'beta' releases.
For development snapshots, a 'devel' suffix is added to distinguish from
the final release. If necessary, the suffix can also be used for 'alpha'
and 'beta' releases.
When linking dynamically, the shared library contains a reference to all
external dependencies, and the linker can easily resolve them. However
when linking statically, all external dependencies have to be specified
explicitly. This rule also applies to dependencies that are not exposed
through the public api.
The pkg-config Requires.private field is used to support both static and
dynamic linking correctly.
