Question about Bind Souce Code

[Pan Renzi]

Hi,all:     I was confused when I read Bind Source Code(9.0.0rc5).     It was in lib/isc/include/isc/types.h,line 62,said like below:     "typedef struct isc_mem isc_mem_t;"      but I cant find any information about "struct isc_mem" anywhere,What's wrong?Is there anyone could give me some idea?     Best Regard.