不好意思,又来请教大家了

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楼主 | 2008-5-11 19:37 | 只看该作者回帖奖励

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unsigned, dc, TE, TI, 函数

C51的库函数有些是再入函数,为什么在头文件里这些库函数的声明里没有使用reentrant　这个关键字？例如：
ＣＴＹＰＥ．Ｈ
#ifndef __CTYPE_H__
#define __CTYPE_H__

#pragma SAVE
#pragma REGPARMS
extern bit isalpha (unsigned char);
extern bit isalnum (unsigned char);
extern bit iscntrl (unsigned char);
extern bit isdigit (unsigned char);
extern bit isgraph (unsigned char);
extern bit isprint (unsigned char);
extern bit ispunct (unsigned char);
extern bit islower (unsigned char);
extern bit isupper (unsigned char);
extern bit isspace (unsigned char);
extern bit isxdigit (unsigned char);
extern unsigned char tolower (unsigned char);
extern unsigned char toupper (unsigned char);
extern unsigned char toint (unsigned char);

#define _tolower(c) ( (c)-'A'+'a' )
#define _toupper(c) ( (c)-'a'+'A' )
#define toascii(c) ( (c) & 0x7F )
#pragma RESTORE

#endif
而我自己试着先声明一个函数，没有用reentrant　这个关键字，再到其它地方定义这个函数并使用reentrant　这个关键字，编译的时候就提示重复定义？

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