Description
bool
function_exists
( string function_name)
Returnerar
TRUE
vid
framgång
eller
FALSE
vid
fel
.
Note that a function name may exist even if the function itself
is unusable due to configuration or compiling options (with the
image
functions being an example). Also note that
function_exists()
will return
FALSE
for constructs, such as
include_once()
and
echo()
.