Problem

Some names, such as kdbOpen, keyNew are so generic that other libraries might also use them. Furthermore, it is inconsistent that some functions have prefixes (e.g. elektraKsFilter) and others don't have (e.g. ksNew).

Constraints

In C such libraries, containing the same external identifier, cannot be used together.
The C99 standard, section 5.2.4.1 gives following limit: 31 significant initial characters in an external identifier (each universal character name specifying a short identifier of 0000FFFF or less is considered 6 characters, each universal character name specifying a short identifier of 00010000 or more is considered 10 characters, and each extended source character is considered the same number of characters as the corresponding universal character name, if any)

Assumptions

Considered Alternatives

leave it as is
use macros to have short names for actually longer external identifiers
use e_ or el_ as shorter prefix

Decision

Ensure all functions start with elektra.
Ensure all macros and constants start with ELEKTRA_.

Rationale

This makes it clear which functions come from Elektra.
Unifies all function names within Elektra (including core).
Avoids collisions with other libs.

Implications

Changes in basically every application and tool, but this is automated with a refactoring tool @kodebach writes.
To be 100% C99 compatible we cannot introduce identifiers which the same 31 character prefix (e.g. ELEKTRA_WARNING_VALIDATION_SYNTACTIC_LEXER and ELEKTRA_WARNING_VALIDATION_SYNTACTIC_PARSER would be a problem). Otherwise, it is not guaranteed that the code can be compiled with every C99 compiler.