c - why typedef is used so widely in nginx? -

for example there many typedefs huge number of structures in ngx_core.h

typedef struct ngx_module_s      ngx_module_t; typedef struct ngx_conf_s        ngx_conf_t; typedef struct ngx_cycle_s       ngx_cycle_t; typedef struct ngx_pool_s        ngx_pool_t; typedef struct ngx_chain_s       ngx_chain_t; typedef struct ngx_log_s         ngx_log_t; typedef struct ngx_array_s       ngx_array_t; typedef struct ngx_open_file_s   ngx_open_file_t; typedef struct ngx_command_s     ngx_command_t; typedef struct ngx_file_s        ngx_file_t; typedef struct ngx_event_s       ngx_event_t; typedef struct ngx_event_aio_s   ngx_event_aio_t; typedef struct ngx_connection_s  ngx_connection_t; 

in fact, know structure name such ngx_module_s ok used, why typedef ngx_module_t? design? and, benefits this?

is kind of practice when programming in c language? and, name of practice? why or bad?

it's common practice. don't have use struct keyword each time declare variable.