Then, we need to create this structure in the process main function. We
could use either gras_userdata_new() or gras_userdata_set(). The former is an
helper macro mallocing the space needed by the structure and passing it to
gras using the latter function. If you go for gras_userdata_set(), you
should pass it a pointer to your data you want to retrieve afterward.
Then, we need to create this structure in the process main function. We
could use either gras_userdata_new() or gras_userdata_set(). The former is an
helper macro mallocing the space needed by the structure and passing it to
gras using the latter function. If you go for gras_userdata_set(), you
should pass it a pointer to your data you want to retrieve afterward.