一旦打开了流，有三种方式。 （1）每次一个字符的I/O。 （2）每次一行的I/O。 （3）直接I/O。 直接I/O（direct I/O）这个属于来自ISO C标准，有时也被称为：二进制I/O、一次一个对象I/O、面向记录的I/O或面向结构的I/O。 输入函数 #include <stdio.h>
int getc(FILE *fp);
int fgetc(FILE *fp);
int getc
二进制I/O #include <stdio.h>
size_t freed(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); （1）读或写一个
#include "apue.h"
int main(void)
{
FILE *fp;
fputs("enter any character\n",stdout);
if(getchar()==EOF)
err_sys("getchar error");
fputs("one line to standard error\n",stderr);
临时文件 提供了两个函数以帮助创建临时文件。 #include <stdio.h>
char *tmpnam(char *ptr);
FILE *tmpfile(void); 嘴多调用次数是TMP_MAX。TMP_MAX定义在 <stdio.h>中。 #include "apue.h"
int main(void)
{
char name[L_tmpnam],line[MAXLINE]
内存流 #include <stdio.h>
FILE *fmemopen(void *restrict buf, size_t size, const char *restrict type); type参数控制如何使用流。 type 说明 r或rb 为读而打开 w或wb 为写而打开 a或ab 追加：为在第一个null字节处写而打开 r+或r+b或rb+ 为读和写而打开 w+或w+b或wb+
口令文件 UNIX系统口令文件（POSIX.1则将其称为用户数据库）包含了下列表格所示的各字段，这些字段包含在<pwd.h>中定义的passwd结构中。 注意，POSIX.1只指定passwd结构包含的10个字段中的5个。大多数平台至少支持其中7各字段。BSD派生的平台支持全部10个字段。 说明 struct passwd成员 POSIX.1 FreeBSD Linux 3.2.0 Mac OS
The function mktime takes a broken-down time, expressed as a local time, and converts it into a time_t value. #include <time.h>
time_t mktime(struct tm *tmptr); The strftime function is a printf-like
偶然发现其实还有第二卷的源码，就一起编译了。 ./configure # try to figure out all implementation differences
cd lib
make
cd ../pipe
make pipeconf
./pipeconf /tmp 有一个错误，提示config.h中 In file included from unpipc.h:7:0,
Command-Line Arguments When a program is executed, the process that does the exec can pass command-line arguments to the new program. This is part of the normal operation of the UNIX system shells. #i
getrlimit and setrlimit Functions Every process has a set of resource limits, some of which can be queried and changed by the getrlimit and setrlimit functions. #include <sys/resource.h>
int getrlimi
exit Function As we described in Section 7.3, a process can terminate normally in five ways: 1.Executing a return from the main function. 2.Calling the exit function. 3.Calling the _exit or _Exit func
exec Functions When a process calls one of the exec functions, that process is completely replaced by the new program, and the new program starts executing at its main function. The process ID does no
Interpreter Files All contemporary UNIX systems support interpreter files. These files are text files that begin with a line of the form #! pathname [ optional-argument ] The space between the exclama
Process Accounting Most UNIX systems provide an option to do process accounting. When enabled, the kernel writes an accounting record each time a process terminates. These accounting records typically
