Upgrading from 1.x¶
This chapter lists the backwards incompatible changes introduced in Jansson 2.0, and the steps that are needed for upgrading your code.
The incompatibilities are not dramatic. The biggest change is that
all decoding functions now require and extra parameter. Most programs
can be modified to work with 2.0 by adding a
0 as the second
parameter to all calls of
Jansson 2.0 is backwards incompatible with the Jansson 1.x releases. It is ABI incompatible, i.e. all programs dynamically linking to the Jansson library need to be recompiled. It’s also API incompatible, i.e. the source code of programs using Jansson 1.x may need modifications to make them compile against Jansson 2.0.
All the 2.x releases are guaranteed to be backwards compatible for both ABI and API, so no recompilation or source changes are needed when upgrading from 2.x to 2.y.
List of Incompatible Changes¶
- Decoding flags
For future needs, a
flagsparameter was added as the second parameter to all decoding functions, i.e.
json_load_file(). All calls to these functions need to be changed by adding a
0as the second argument. For example:
/* old code */ json_loads(input, &error); /* new code */ json_loads(input, 0, &error);
- Underlying type of JSON integers
The underlying C type of JSON integers has been changed from
intto the widest available signed integer type, i.e.
long, depending on whether
long longis supported on your system or not. This makes the whole 64-bit integer range available on most modern systems.
jansson.hhas a typedef
json_int_tto the underlying integer type.
intshould still be used in most cases when dealing with smallish JSON integers, as the compiler handles implicit type coercion. Only when the full 64-bit range is needed,
json_int_tshould be explicitly used.
- Maximum encoder indentation depth
- The maximum argument of the
JSON_INDENT()macro has been changed from 255 to 31, to free up bits from the
json_dump_file(). If your code uses a bigger indentation than 31, it needs to be changed.
- Unsigned integers in API functions
- Version 2.0 unifies unsigned integer usage in the API. All uses of
unsigned longhave been replaced with
size_t. This includes flags, container sizes, etc. This should not require source code changes, as both
unsigned longare usually compatible with