Introduced header version macros into libisofs.h

This commit is contained in:
Thomas Schmitt 2008-01-31 19:38:54 +01:00
parent 16cfaf9059
commit cbe33c9df2
1 changed files with 65 additions and 2 deletions

View File

@ -567,19 +567,82 @@ void iso_finish();
*/
int iso_image_new(const char *name, IsoImage **image);
/** The following two functions three macros are utilities to help ensuring
version match of application, compile time header, and runtime library.
*/
/**
* Get version of the libisofs library.
* Get version of the libisofs library at runtime.
*/
void iso_lib_version(int *major, int *minor, int *micro);
/**
* Check if the library is ABI compatible with the given version.
* Check at runtime if the library is ABI compatible with the given version.
*
* @return
* 1 lib is compatible, 0 is not.
*/
int iso_lib_is_compatible(int major, int minor, int micro);
/** These three release version numbers tell the revision of this header file
and of the API it describes. They are memorized by applications at
compile time.
They must show the same values as these symbols in ./configure.ac
LIBISOFS_MAJOR_VERSION=...
LIBISOFS_MINOR_VERSION=...
LIBISOFS_MICRO_VERSION=...
Note to anybody who does own work inside libisofs:
Any change of configure.ac or libisofs.h has to keep up this equality !
*/
#define iso_lib_header_version_major 0
#define iso_lib_header_version_minor 6
#define iso_lib_header_version_micro 1
/** Usage discussion:
Some developers of the libburnia project have differing
opinions how to ensure the compatibility of libaries
and applications.
It is about whether to use at compile time and at runtime
the version numbers provided here.
Thomas Schmitt advises to use them.
Vreixo Formoso advises to use other means.
At compile time:
Vreixo Formoso advises to leave proper version matching
to properly programmed checks in the the application's
build system, which will eventually refuse compilation.
Thomas Schmitt advises to use the macros defined here
for comparison with the application's requirements of
library revisions and to eventually break compilation.
Both advises are combinable. I.e. be master of your
build system and have #if checks in the source code
of your application, nevertheless.
At runtime (via *_is_compatible()):
Vreixo Formoso advises to compare the application's
requirements of library revisions with the runtime
library. This is to allow runtime libraries which are
young enough for the application but too old for
the lib*.h files seen at compile time.
Thomas Schmitt advises to compare the header
revisions defined here with the runtime library.
This is to enforce a strictly monotonous chain
of revisions from app to header to library,
at the cost of excluding some older libraries.
These two advises are mutually exclusive.
*/
/**
* Creates an IsoWriteOpts for writing an image. You should set the options
* desired with the correspondent setters.