数据类型取值范围

[further@fedora12 linux]$ pwd

/usr/include/linux

[further@fedora12 linux]$ ls l*s.h

limits.h

[further@fedora12 linux]$ cat limits.h

#ifndef _LINUX_LIMITS_H

#define _LINUX_LIMITS_H

 

#define NR_OPEN         1024

 

#define NGROUPS_MAX    65536    /* supplemental group IDs are available */

#define ARG_MAX       131072      /* # bytes of args + environ for exec() */

#define LINK_MAX         127      /* # links a file may have */

#define MAX_CANON        255    /* size of the canonical input queue */

#define MAX_INPUT        255      /* size of the type-ahead buffer */

#define NAME_MAX         255     /* # chars in a file name */

#define PATH_MAX        4096      /* # chars in a path name including nul */

#define PIPE_BUF        4096  /* # bytes in atomic write to a pipe */

#define XATTR_NAME_MAX   255  /* # chars in an extended attribute name */

#define XATTR_SIZE_MAX 65536      /* size of an extended attribute value (64k) */

#define XATTR_LIST_MAX 65536     /* size of extended attribute namelist (64k) */

 

#define RTSIG_MAX      32

 

#endif

 

 

Signed short int -32768 ~ 32767

Unsigned short int 0 ~ 65535

 

两者之间的交集： 0 ~ 32767， 可以获得最大程度上的可移植性，同时又不牺牲性能