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Cairo: A Vector Graphics Library | ![]() |
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#define CAIRO_VERSION #define CAIRO_VERSION_MAJOR #define CAIRO_VERSION_MINOR #define CAIRO_VERSION_MICRO #define CAIRO_VERSION_STRING #define CAIRO_VERSION_ENCODE (major, minor, micro) int cairo_version (void); const char* cairo_version_string (void);
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 CVS instead of a tar file, or as a "snapshot" tar file as opposed to a "release" tar file).
_____ Major. Always 1, until we invent a new scheme. / ___ Minor. Even/Odd = Release/Snapshot (tar files) or Branch/Head (CVS) | / _ Micro. Even/Odd = Tar-file/CVS | | / 1.0.0
Here are a few examples of versions that one might see.
Releases -------- 1.0.0 - A major release 1.0.2 - A subsequent maintenance release 1.2.0 - Another major release Snapshots --------- 1.1.2 - A snapshot (working toward the 1.2.0 release) In-progress development (eg. from CVS) -------------------------------------- 1.0.1 - Development on a maintenance branch (toward 1.0.2 release) 1.1.1 - Development on head (toward 1.1.2 snapshot and 1.2.0 release)
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.
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 a macro (CAIRO_VERSION_ENCODE) to perform the encoding.
Compile-time ------------CAIRO_VERSION_STRING
Human-readableCAIRO_VERSION
Encoded, suitable for comparison Run-time --------cairo_version_string()
Human-readablecairo_version()
Encoded, suitable for comparison
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:
#ifCAIRO_VERSION
>=CAIRO_VERSION_ENCODE
(1, 0, 0) printf ("Compiling with suitable cairo version: %s
\n", CAIRO_VERSION_STRING); #endif if (cairo_version()
>=CAIRO_VERSION_ENCODE
(1, 0, 0)) printf ("Running with suitable cairo version: %s
\n",cairo_version_string()
);