Hi Pietro.
That check comes from the similar code in libpoke:
void
pvm_alloc_initialize ()
{
/* Initialize the Boehm Garbage Collector, but only if it hasn't
been already initialized. The later may happen if some other
library or program uses the boehm GC. */
if (!GC_is_init_called ())
{
GC_INIT ();
GC_allow_register_threads ();
}
}
Which, as the comment explain, is an attempt to _try_ to coexist with
other applications/libs using the Boehm GC. I looked at the GC_INIT
macro definition in my gc/gc.h:
#define GC_INIT() { GC_INIT_CONF_DONT_EXPAND; /* pre-init */ \
GC_INIT_CONF_FORCE_UNMAP_ON_GCOLLECT; \
GC_INIT_CONF_MAX_RETRIES; \
GC_INIT_CONF_FREE_SPACE_DIVISOR; \
GC_INIT_CONF_FULL_FREQ; \
GC_INIT_CONF_TIME_LIMIT; \
GC_INIT_CONF_SUSPEND_SIGNAL; \
GC_INIT_CONF_THR_RESTART_SIGNAL; \
GC_INIT_CONF_MAXIMUM_HEAP_SIZE; \
GC_init(); /* real GC initialization */ \
GC_INIT_CONF_ROOTS; /* post-init */ \
GC_INIT_CONF_IGNORE_WARN; \
GC_INIT_CONF_INITIAL_HEAP_SIZE; }
Doesn't look like a nop when GC_is_init_called returns true.. The
macros before and after GC_init call functions to alter the global state
of the allocator, unless these are guarded internally.
> GC_INIT() checks if the GC is has already been initialized.
> Don't check it a second time.
>
> libga68/ChangeLog:
>
> PR algol68/123733
> * ga68-alloc.c (_libga68_init_heap):
>
> Signed-off-by: Pietro Monteiro <[email protected]>
> ---
> libga68/ga68-alloc.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/libga68/ga68-alloc.c b/libga68/ga68-alloc.c
> index df8a8956c52..0a749cd5984 100644
> --- a/libga68/ga68-alloc.c
> +++ b/libga68/ga68-alloc.c
> @@ -48,11 +48,8 @@ _libga68_malloc_internal (size_t size)
> void
> _libga68_init_heap (void)
> {
> - if (!GC_is_init_called ())
> - {
> - GC_INIT ();
> - /* GC_allow_register_threads (); */
> - }
> + GC_INIT ();
> + /* GC_allow_register_threads (); */
> }
>
> void *
>
> base-commit: 2d626c4eb68a33a13a3d497364c493f3b71fb9e7
