Debug size_t

调试BUG时发现，以下问题:

由代码中发现

BYTES_INVALID 定义如下:

奇怪问题:在于file->write_size == -1; 但是if判断中却没有走到contine代码分支, 而是继续走到 validate.c 351行输出;

关于数据结构定义如下:

typedef struct pgFile
{
	time_t	mtime;			/* time of last modification */
	mode_t	mode;			/* protection (file type and permission) */
	size_t	size;			/* size of the file */
	size_t	read_size;		/* size of the portion read (if only some pages are
							   backed up partially, it's different from size) */
	size_t	write_size;		/* size of the backed-up file. BYTES_INVALID means
							   that the file existed but was not backed up
							   because not modified since last backup. */
	pg_crc32c crc;			/* CRC value of the file, regular file only */
	char   *linked;			/* path of the linked file */
	bool	is_datafile;	/* true if the file is PostgreSQL data file */
	char	path[1]; 		/* path of the file */
} pgFile;

查看sizeof大小:

sizeof(size_t)

window: 8字节;

linux: 8字节;

cppreference.com size_t页面

​ size_t 是 sizeof 、 _Alignof (C11 起) 和 offsetof 的结果的无符号整数类型，定义取决于数据模型。

size_t 定义如下:

typedef unsigned int size_t;  //8Byte

Linux size_t 应该用 %u 标识, 即 -1 应该为 4294967295;

按照内存格式输出:

printf("%u   %d", -1, -1);

输出为

4294967295  -1

即修改代码:

#ifdef WIN32
#define BYTES_INVALID			(4294967295)
#else
#define BYTES_INVALID			(-1)
#endi