Version Information
Version Information — Compile-time and run-time version checks.
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Description
Cairo has a three-part version number scheme. In this scheme, we use
even vs. odd numbers to distinguish fixed points in the software
vs. in-progress development, (such as from git instead of a tar file,
or as a "snapshot" tar file as opposed to a "release" tar file).
Here are a few examples of versions that one might see.
Compatibility
The API/ABI compatibility guarantees for various versions are as
follows. First, let's assume some cairo-using application code that is
successfully using the API/ABI "from" one version of cairo. Then let's
ask the question whether this same code can be moved "to" the API/ABI
of another version of cairo.
Moving from a release to any later version (release, snapshot,
development) is always guaranteed to provide compatibility.
Moving from a snapshot to any later version is not guaranteed to
provide compatibility, since snapshots may introduce new API that ends
up being removed before the next release.
Moving from an in-development version (odd micro component) to any
later version is not guaranteed to provide compatibility. In fact,
there's not even a guarantee that the code will even continue to work
with the same in-development version number. This is because these
numbers don't correspond to any fixed state of the software, but
rather the many states between snapshots and releases.
Examining the version
Cairo provides the ability to examine the version at either
compile-time or run-time and in both a human-readable form as well as
an encoded form suitable for direct comparison. Cairo also provides the
macro
CAIRO_VERSION_ENCODE() to perform the encoding.
For example, checking that the cairo version is greater than or equal
to 1.0.0 could be achieved at compile-time or run-time as follows:
Functions
CAIRO_VERSION_ENCODE()
#define CAIRO_VERSION_ENCODE(major, minor, micro)
This macro encodes the given cairo version into an integer. The numbers
returned by CAIRO_VERSION and cairo_version() are encoded using this macro.
Two encoded version numbers can be compared as integers. The encoding ensures
that later versions compare greater than earlier versions.
Returns
the encoded version.
Since: 1.0
CAIRO_VERSION_STRINGIZE()
#define CAIRO_VERSION_STRINGIZE(major, minor, micro)
This macro encodes the given cairo version into an string. The numbers
returned by CAIRO_VERSION_STRING and cairo_version_string() are encoded using this macro.
The parameters to this macro must expand to numerical literals.
Returns
a string literal containing the version.
Since: 1.8
cairo_version ()
int
cairo_version (void);
Returns the version of the cairo library encoded in a single
integer as per CAIRO_VERSION_ENCODE. The encoding ensures that
later versions compare greater than earlier versions.
A run-time comparison to check that cairo's version is greater than
or equal to version X.Y.Z could be performed as follows:
See also cairo_version_string() as well as the compile-time
equivalents CAIRO_VERSION and CAIRO_VERSION_STRING.
Returns
the encoded version.
Since: 1.0
cairo_version_string ()
const char *
cairo_version_string (void);
Returns the version of the cairo library as a human-readable string
of the form "X.Y.Z".
See also cairo_version() as well as the compile-time equivalents
CAIRO_VERSION_STRING and CAIRO_VERSION.
Returns
a string containing the version.
Since: 1.0
Types and Values
CAIRO_VERSION
#define CAIRO_VERSION
The version of cairo available at compile-time, encoded using
CAIRO_VERSION_ENCODE().
Since: 1.0
CAIRO_VERSION_MAJOR
#define CAIRO_VERSION_MAJOR USE_cairo_version_OR_cairo_version_string_INSTEAD
The major component of the version of cairo available at compile-time.
Since: 1.0
CAIRO_VERSION_MINOR
#define CAIRO_VERSION_MINOR USE_cairo_version_OR_cairo_version_string_INSTEAD
The minor component of the version of cairo available at compile-time.
Since: 1.0
CAIRO_VERSION_MICRO
#define CAIRO_VERSION_MICRO USE_cairo_version_OR_cairo_version_string_INSTEAD
The micro component of the version of cairo available at compile-time.
Since: 1.0
CAIRO_VERSION_STRING
#define CAIRO_VERSION_STRING
A human-readable string literal containing the version of cairo available
at compile-time, in the form of "X.Y.Z".
Since: 1.8