我们在pixman直接查找pixman_region32_init实现会找不到，原因在于PREFIX宏
1、在pixman-region32.c和pixman-region16.c有很大关系，以pixman-region32.c为例
#ifdef HAVE_CONFIG_H
#include <pixman-config.h>
#endif
#include "pixman-private.h"
#include <stdlib.h>typedef pixman_box32_t box_type_t;
typedef pixman_region32_data_t region_data_type_t;
typedef pixman_region32_t region_type_t;
typedef int64_t overflow_int_t;typedef struct {int x, y;
} point_type_t;#define PREFIX(x) pixman_region32##x#define PIXMAN_REGION_MAX INT32_MAX
#define PIXMAN_REGION_MIN INT32_MIN#include "pixman-region.c"原因就在于： PREFIX(x)宏的展开
2、pixman_region32_init的真正实现函数就在这里
PIXMAN_EXPORT void
PREFIX (_init) (region_type_t *region)
{region->extents = *pixman_region_empty_box;region->data = pixman_region_empty_data;
}
——RAID与服务器的常见故障)
