#include<stdo.h>
#include<wchar.h>int fwide(FILE *fp,int mode);返回值：若流是宽定向的则返回正值，若流是字节定向的则返回负值，未定向则返回0

#include<stdio.h>void setbuf(FILE *restrict fp,char *restrict buf);int setvbuf(FILE *restrict,char *restrict buf,int mode,size_t size);返回值：若成功则返回0，若出错则返回非0值

#include<stdio.h>int fflush(FILE *fp);返回值：若成功则返回0，若出错则返回EOF

#include<stdio.h>FILE *fopen(const char *restrict pathname,const char *restrict type);   FILE *freopen(const char *restrict pathname,const char *restrict type,FILE *restrict fp);FILE *fdopen(int filedes,const char *type);三个函数返回值：若成功则返回文件指针，若出错则返回NULL

#include<stdio.h>int fclose(FILE *fp);返回值：若成功则返回0，若出错则返回EOF

#include<stdio.h>int getc(FILE *fp);int fgetc(FILE *fp);int getchar(void);//三个函数的返回值：若成功则返回下一个字符，若已达到文件结尾或出错则返回EOF

#include<stdio.h>int ferror(FILE *fp);int feof(FILE *fp);//两个函数返回值：若条件为真则返回非0值，否者返回0
void clearerr(FILE *fp);

#include<stdio.h>int ungetc(int c,FILE *fp);//返回值：若成功则返回c，若出错则返回EOF

#include<stdio.h>int putc(int c ,FILE *fp);int fputc(int c,FILE *fp);int putchar(int c);三个函数返回值：若成功则返回c，若出错则返回EOF

#include<stdio.h>char *fgets(char *restrict buf ,int n,FILE *restrict fp);char *gets(char *buf);//两个函数返回值：若成功则返回buf，若已达到文件结尾或出错则返回NULL

#include<stdio.h>int fputs(const char *restrict str,FILE *restrict fp);int puts(const char *str);//两个函数返回值:若成功则返回非负值，若出错则返回EOF

 1 #include"apue.h"
 2 int main()
 3 {
 4     int c;
 5     while((c=getc(stdin))!=EOF)
 6         if(putc(c,stdout)==EOF)
 7             err_sys("output error");
 8     if(ferror(stdin))
 9         err_sys("input error");
10     exit(0);
11 }

 1 #include"apue.h"
 2
 3 int main()
 4 {
 5     char buf[MAXLINE];
 6     while(fgets(buf,MAXLINE,stdin)!=NULL)
 7         if(fputs(buf,stdout)==EOF)
 8         err_sys("output error");
 9     if(ferror(stdin))
10         err_sys("input error");
11     exit(0);
12 }

#include<stdio.h>size_t fread(void *restrict ptr,size_t size,size_t nobj,FILE *restrict fp);size_t fwrite(const void *restrict ptr,size_t size,size_t nobj,FILE *restrict fp);//两个函数的返回值：读或写的对象数

float data[10];
if(fwrite(&data[2],sizeof(float),4,fp)!=4)err_sys("fwrite error");

struct{short count;long total;char name[NAMESIZE];
}item;
if(fwrite(&item,sizeof(item),1,fp)!=1)err_sys("fwrite error");

#include<stdio.h>long ftell(FILE *fp);//返回值：若成功则返回当前文件位置指示，若出错则返回-1in fseek(FILE *fp,long offset,int whence);//返回值：若成功则返回0，若出错则返回非0值void rewind(FILE *fp);off_t ftello(FILE *fp);//返回值：若成功则返回当前文件位置指示，若出错则返回-1int fseeko（FILE *fp,off_t offset,int whence);//返回值：若成功则返回0，若出错则返回非0值int fgetpos(FILE *restrict fp,fpos_t *restrict pos);int fsetpos(FILE *fp,const fpos_t *pos);//两个函数返回值：若成功则返回0，若出错则返回非0值

#include<stdio.h>int printf(const char *restrict format);int fprintf(FILE *restrict fp,const char *restrict format,...);//两个函数返回值：若成功则返回输出字符数，若输出出错则返回负值
int sprintf(char *restrict buf,const char *restrict format,...);int snprintf(char *restrict buf,size_t n,const char *restrict format,...);//两个函数返回值：若成功则返回存入数组的字符数，若编码出错则返回负值

#include<stdio.h>int scanf(const char *restrict format, ...);int fcanf(FILE *restrict fp,const char *restrict format, ...);int sscanf(const char *restrict buf, const char *restrict format, ...);//三个函数返回值：指定的输入项数；若输入出错或在任意变换前已到达文件结尾则返回EOF

#include<stdio.h>
int fileno(FILE *fp);//返回值：与该流相关联的文件描述符

 1 #include"apue.h"
 2 void pr_stdio(const char *,FILE *);
 3
 4 int main()
 5 {
 6     FILE *fp;
 7     fputs("enter any character\n",stdout);
 8     if(getchar()==EOF)
 9         err_sys("getchar error");
10     fputs("one line to standard error\n",stderr);
11
12     pr_stdio("stdin",stdin);
13     pr_stdio("stdout",stdout);
14     pr_stdio("stderr",stderr);
15
16     if((fp=fopen("/etc/host.conf","r"))==NULL)
17         err_sys("fopen error");
18     if(getc(fp)==EOF)
19         err_sys("getc error");
20     pr_stdio("/etc/host.conf",fp);
21     exit(0);
22 }
23 void pr_stdio(const char *name,FILE *fp)
24 {
25     printf("stream = %s, ",name);
26     /*
27      *The following is nonportable
28      */
29     if(fp->_IO_file_flags&_IO_UNBUFFERED)
30         printf("unbuffered");
31     else if(fp->_IO_file_flags&_IO_LINE_BUF)
32         printf("line buffered");
33     else
34         printf("fully buffered");
35     printf(", buffer size = %d\n",fp->_IO_buf_end - fp->_IO_buf_base);
36 }

#include<stdio.h>char *tmpnam(char *ptr);//返回值：指向惟一路径名的指针
FILE *tmpfile(void);//返回值：若成功则返回文件指针，若出错则返回NULL

 1 #include"apue.h"
 2 int main()
 3 {
 4     char name[L_tmpnam],line[MAXLINE];
 5     FILE *fp;
 6     printf("%s\n",tmpnam(NULL)); //first temp name
 7     tmpnam(name);        //second temp name
 8     printf("%s\n",name);
 9     if((fp=tmpfile())==NULL)        //creat temp file
10     err_sys("tmpfile error");
11     fputs("one line of output\n",fp);    //write to temp file
12     rewind(fp);            //then read it back
13     if(fgets(line,sizeof(line),fp)==NULL)
14         err_sys("fgets error");
15     fputs(line,stdout);        //print the line we wrote
16     exit(0);
17 } 

#include<stdio.h>char *tempnam(const char *directory,const char *prefix);//返回值：指向唯一路径名的指针

 1 #include"apue.h"
 2
 3 int main(int argc,char *argv[])
 4 {
 5     if(argc!=3)
 6     err_quit("usage:a.out <directory><prefix>");
 7
 8     printf("%s\n",tempnam(argv[1][0]!=' ' ? argv[1]:NULL,
 9         argv[2][0]!=' ' ? argv[2]:NULL));
10     exit(0);
11 }

#include<stdlib.h>int mkstemp(char *template);//返回值:若成功则返回文件描述符，若出错则返回-1