谁能一起来分析一下这个API
errlog_open Subroutine （摘自AIX5.2 Technical Reference: Base Operating System and Extensions, Volume 1）
Purpose
Opens an error log and returns a handle for use with other liberrlog.a functions.
Syntax
library liberrlog.a
#include <fcntl.h>
#include <sys/errlog.h>
int errlog_open(path, mode, magic, handle)
char *path; int mode; unsigned int magic;
errlog_handle_t *handle;
Description
The error log specified by the path argument will be opened using mode. The handle pointed to by the handle parameter must be used with subsequent operations.
Parameters
The path parameter specifies the path to the log file to be opened. If path is NULL, the default errlog file will be opened. The valid values for mode are the same as they are for the open system subroutine. They can be found in the fcntl.h files. The magic argument takes the LE_MAGIC value, indicating which version of the errlog_entry_t structure this application was compiled with.
Return Values
Upon successful completion, the errlog_open subroutine returns a 0 and sets the memory pointed to by handle to a handle used by subsequent liberrlog operations.
Upon error, the errlog_open subroutine returns one of the following:
LE_ERR_INVARG A parameter error was detected.
LE_ERR_NOFILE The log file does not exist.
LE_ERR_NOMEM Memory could not be allocated.
LE_ERR_IO An i/o error occurred.
LE_ERR_INVFILE The file is not a valid error log.
我在开发一个监控AIX system error log的程序，虽然用shell更简单一些，但我必须用C来实现它。上面这个API就是用来打开system error log的系统调用，在程序中这个系统调用返回值为１，请问我如何判断错误返回类型是：LE_ERR_INVARG LE_ERR_NOFILE LE_ERR_NOMEM LE_ERR_IO LE_ERR_INVFILE中的哪一种？
以下是我的程序代码及运行输出，请帮忙查看我的程序和方法是否有错误？（共两个问题）
asm@zhguowen_sv:/asmdev/asm$vi errlog_op.c
"errlog_op.c " 30 lines, 509 characters
#include <stdio.h>
#include <fcntl.h>
#include <sys/errlog.h>
#include <libperfstat.h>
int mode;
unsigned int magic;
errlog_handle_t hl;
main()
{
mode=0;
magic=LE_MAGIC;
int rc,ac;
char path[]= "/var/adm/ras/errlog ";
int er_dir=LE_REVERSE;
rc=errlog_open(path,mode,magic,hl);
sleep(1);
if (rc==0) { printf( "\nopen errlog sucessful!\n "); }
else
{
printf( "\nopen errlog failed!rc=%i\n ",rc);
}
ac=errlog_set_direction(hl,er_dir);
printf( "\n ac= %i ",ac);
}
~~
:q!
asm@zhguowen_sv:/asmdev/asm$cc -lperfstat errlog_op.c /usr/lib/liberrlog.a
asm@zhguowen_sv:/asmdev/asm$./a.out
open errlog failed!rc=1
ac= １
[解决办法]
1. 请问我如何判断错误返回类型是：LE_ERR_INVARG LE_ERR_NOFILE LE_ERR_NOMEM LE_ERR_IO LE_ERR_INVFILE中的哪一种？
====
用switch (rc) 或if (LE_ERR_INVARG == rc)
