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vc6.0 编译时出现两个问题（二手转帖）

楼主languagec（各有所求）2006-03-03 18:49:53 在 C/C++ / 工具平台和程序库提问

2.2 例子程序
自己写一个例子程序似乎不可行，如果您已经能自己写一个SNMP程序了，那么这篇文章就不要看了吧。我们直接用一个MSDN上的例子吧。在VS6的Msdn上有这么一个例子在...\Samples\VC98\SDK\NETDS\SNMP\SNMPUTIL下面。有意思的是这个例子的Readme里面也没有讲运行的时候需要什么条件。可以理解的原因是这种程序不是用在本机PC上的，而是控制路由器等远程网络设备的。

虽然相信很多地方都可以找到这个程序，但是我还是把它的代码贴到这里，一来显得文章有了“份量”。二来为了给少数机器上没有装全msdn的人一个方便。三来这个代码我稍微做了一点修改，在出错的时候打印出了出错原因的字符描述，原来的例子给出的是整数的代码。让人不能直观地知道是什么原因。

这个例子是console程序，没有任何窗体、对话框。而且就一个.C文件，也很方便贴出来。另外还有一个MAKEFILE文件，这里就不列出了。

以下是SNMPUTIL.C文件：

/*++ BUILD Version: 0001 // Increment this if a change has global effects

Copyright (c) 1991-1995 Microsoft Corporation

Module Name:

snmputil.c

Abstract:

Sample SNMP Management API usage for Windows NT.

This file is an example of how to code management applications using
the SNMP Management API for Windows NT. It is similar in operation to
the other commonly available SNMP command line utilities.

Extensive comments have been included to describe its structure and
operation. See also "Microsoft Windows/NT SNMP Programmer's Reference".

Created:

28-Jun-1991

Revision History:

--*/

static char *vcsid = "@(#) $Logfile: N:/agent/mgmtapi/vcs/snmputil.c_v $ $Revision: 1.5 $";

// General notes:
// Microsoft's SNMP Management API for Windows NT is implemented as a DLL
// that is linked with the developer's code. These APIs (examples follow in
// this file) allow the developer's code to generate SNMP queries and receive
// SNMP traps. A simple MIB compiler and related APIs are also available to
// allow conversions between OBJECT IDENTIFIERS and OBJECT DESCRIPTORS.

// Necessary includes.

#include <windows.h>

#include <stdio.h>
#include <string.h>
#include <malloc.h>

#include <snmp.h>
#include <mgmtapi.h>

// Constants used in this example.

#define GET 1
#define GETNEXT 2
#define WALK 3
#define TRAP 4

#define TIMEOUT 6000 /* milliseconds */
#define RETRIES 3

// Main program.

INT _CRTAPI1 main(
IN int argumentCount,
IN char *argumentVector[])

{
INT operation;
LPSTR agent;
LPSTR community;
RFC1157VarBindList variableBindings;
LPSNMP_MGR_SESSION session;

INT timeout = TIMEOUT;
INT retries = RETRIES;

BYTE requestType;
AsnInteger errorStatus;
AsnInteger errorIndex;
char *chkPtr = NULL;

// Parse command line arguments to determine requested operation.

// Verify number of arguments...
if (argumentCount < 5 && argumentCount != 2)
{
printf("Error: Incorrect number of arguments specified.\n");
printf(
"\nusage: snmputil [get|getnext|walk] agent community oid [oid ...]\n");
printf(
" snmputil trap\n");

return 1;
}

// Get/verify operation...
argumentVector++;
argumentCount--;
if (!strcmp(*argumentVector, "get"))
operation = GET;
else if (!strcmp(*argumentVector, "getnext"))
operation = GETNEXT;
else if (!strcmp(*argumentVector, "walk"))
operation = WALK;
else if (!strcmp(*argumentVector, "trap"))
operation = TRAP;
else
{
printf("Error: Invalid operation, '%s', specified.\n",
*argumentVector);

return 1;
}

if (operation != TRAP)
{
if (argumentCount < 4)
{
printf("Error: Incorrect number of arguments specified.\n");
printf(
"\nusage: snmputil [get|getnext|walk] agent community oid [oid ...]\n");
printf(
" snmputil trap\n");

return 1;
}

// Get agent address...
argumentVector++;
argumentCount--;
agent = (LPSTR)SNMP_malloc(strlen(*argumentVector) + 1);
strcpy(agent, *argumentVector);

// Get agent community...
argumentVector++;
argumentCount--;
community = (LPSTR)SNMP_malloc(strlen(*argumentVector) + 1);
strcpy(community, *argumentVector);

// Get oid's...
variableBindings.list = NULL;
variableBindings.len = 0;

while(--argumentCount)
{
AsnObjectIdentifier reqObject;

argumentVector++;

// Convert the string representation to an internal representation.
if (!SnmpMgrStrToOid(*argumentVector, &reqObject))
{
printf("Error: Invalid oid, %s, specified.\n", *argumentVector);

return 1;
}
else
{
// Since sucessfull, add to the variable bindings list.
variableBindings.len++;
if ((variableBindings.list = (RFC1157VarBind *)SNMP_realloc(
variableBindings.list, sizeof(RFC1157VarBind) *
variableBindings.len)) == NULL)
{
printf("Error: Error allocating oid, %s.\n",
*argumentVector);

return 1;
}

variableBindings.list[variableBindings.len - 1].name =
reqObject; // NOTE! structure copy
variableBindings.list[variableBindings.len - 1].value.asnType =
ASN_NULL;
}
} // end while()

// Make sure only one variable binding was specified if operation
// is WALK.
if (operation == WALK && variableBindings.len != 1)
{
printf("Error: Multiple oids specified for WALK.\n");

return 1;
}

// Establish a SNMP session to communicate with the remote agent. The
// community, communications timeout, and communications retry count
// for the session are also required.

问题点数：100、回复次数：4Top

1 楼languagec（各有所求）回复于 2006-03-03 18:53:58 得分 0

if ((session = SnmpMgrOpen(agent, community, timeout, retries)) == NULL)
{
printf("error on SnmpMgrOpen %d\n", GetLastError());

return 1;
}

} // end if(TRAP)

// Determine and perform the requested operation.

if (operation == GET || operation == GETNEXT)
{
// Get and GetNext are relatively simple operations to perform.
// Simply initiate the request and process the result and/or
// possible error conditions.

if (operation == GET)
requestType = ASN_RFC1157_GETREQUEST;
else
requestType = ASN_RFC1157_GETNEXTREQUEST;

// Request that the API carry out the desired operation.

if (!SnmpMgrRequest(session, requestType, &variableBindings,
&errorStatus, &errorIndex))
{
// The API is indicating an error.

printf("error on SnmpMgrRequest %d\n", GetLastError());
}
else
{
// The API succeeded, errors may be indicated from the remote
// agent.
switch(errorStatus)
{
case SNMP_ERRORSTATUS_TOOBIG:
{
printf("SNMP_ERRORSTATUS_TOOBIG");
break;
}
case SNMP_ERRORSTATUS_NOSUCHNAME:
{
printf("SNMP_ERRORSTATUS_NOSUCHNAME");
break;
}
case SNMP_ERRORSTATUS_BADVALUE:
{
printf("SNMP_ERRORSTATUS_BADVALUE");
break;
}
default:
break;
}
if (errorStatus > 0)
{
printf("Error: errorStatus=%d, errorIndex=%d\n",
errorStatus, errorIndex);
}
else
{
// Display the resulting variable bindings.

UINT i;
char *string = NULL;

for(i=0; i < variableBindings.len; i++)
{
SnmpMgrOidToStr(&variableBindings.list[i].name, &string);
printf("Variable = %s\n", string);
if (string) SNMP_free(string);

printf("Value = ");
SnmpUtilPrintAsnAny(&variableBindings.list[i].value);

printf("\n");
} // end for()
}

// Free the variable bindings that have been allocated.
SnmpUtilVarBindListFree(&variableBindings);
}
}
else if (operation == WALK)
{
// Walk is a common term used to indicate that all MIB variables
// under a given OID are to be traversed and displayed. This is
// a more complex operation requiring tests and looping in addition
// to the steps for get/getnext above.

AsnObjectIdentifier root;
AsnObjectIdentifier tempOid;

SnmpUtilOidCpy(&root, &variableBindings.list[0].name);

requestType = ASN_RFC1157_GETNEXTREQUEST;

while(1)
{
if (!SnmpMgrRequest(session, requestType, &variableBindings,
&errorStatus, &errorIndex))
{
// The API is indicating an error.

printf("error on SnmpMgrRequest %d\n", GetLastError());

break;
}
else
{
// The API succeeded, errors may be indicated from the remote
// agent.

// Test for end of subtree or end of MIB.

if (errorStatus == SNMP_ERRORSTATUS_NOSUCHNAME ||
SnmpUtilOidNCmp(&variableBindings.list[0].name,
&root, root.idLength))
{
printf("End of MIB subtree.\n\n");

break;
}

// Test for general error conditions or sucesss.

if (errorStatus > 0)
{
printf("Error: errorStatus=%d, errorIndex=%d \n",
errorStatus, errorIndex);

break;
}
else
{
// Display resulting variable binding for this iteration.

char *string = NULL;

SnmpMgrOidToStr(&variableBindings.list[0].name, &string);
printf("Variable = %s\n", string);
if (string) SNMP_free(string);

printf("Value = ");
SnmpUtilPrintAsnAny(&variableBindings.list[0].value);

printf("\n");
}
} // end if()

// Prepare for the next iteration. Make sure returned oid is
// preserved and the returned value is freed.

SnmpUtilOidCpy(&tempOid, &variableBindings.list[0].name);

SnmpUtilVarBindFree(&variableBindings.list[0]);

SnmpUtilOidCpy(&variableBindings.list[0].name, &tempOid);
variableBindings.list[0].value.asnType = ASN_NULL;

SnmpUtilOidFree(&tempOid);

} // end while()

// Free the variable bindings that have been allocated.

SnmpUtilVarBindListFree(&variableBindings);

SnmpUtilOidFree(&root);

}
else if (operation == TRAP)
{
// Trap handling can be done two different ways: event driven or
// polled. The following code illustrates the steps to use event
// driven trap reception in a management application.

HANDLE hNewTraps = NULL;

if (!SnmpMgrTrapListen(&hNewTraps))
{
printf("error on SnmpMgrTrapListen %d\n", GetLastError());
}
else
{
printf("snmputil: listening for traps...\n");
}

Top

2 楼languagec（各有所求）回复于 2006-03-03 18:54:12 得分 0

while(1)
{
DWORD dwResult;

if ((dwResult = WaitForSingleObject(hNewTraps, 0xffffffff))
== 0xffffffff)
{
printf("error on WaitForSingleObject %d\n",
GetLastError());
}
else if (!ResetEvent(hNewTraps))
{
printf("error on ResetEvent %d\n", GetLastError());
}
else
{
AsnObjectIdentifier enterprise;
AsnNetworkAddress IPAddress;
AsnInteger genericTrap;
AsnInteger specificTrap;
AsnTimeticks timeStamp;
RFC1157VarBindList variableBindings;

UINT i;
char *string = NULL;

while(SnmpMgrGetTrap(&enterprise, &IPAddress, &genericTrap,
&specificTrap, &timeStamp, &variableBindings))
{
printf("snmputil: trap generic=%d specific=%d\n",
genericTrap, specificTrap);
if (IPAddress.length == 4) {
printf(" from -> %d.%d.%d.%d\n",
(int)IPAddress.stream[0], (int)IPAddress.stream[1],
(int)IPAddress.stream[2], (int)IPAddress.stream[3]);

}
if (IPAddress.dynamic) {
SNMP_free(IPAddress.stream);
}

for(i=0; i < variableBindings.len; i++)
{
SnmpMgrOidToStr(&variableBindings.list[i].name, &string);
printf("Variable = %s\n", string);
if (string) SNMP_free(string);

printf("Value = ");
SnmpUtilPrintAsnAny(&variableBindings.list[i].value);
} // end for()
printf("\n");

SnmpUtilOidFree(&enterprise);

SnmpUtilVarBindListFree(&variableBindings);
}
}
} // end while()

} // end if(operation)

if (operation != TRAP)
{
// Close SNMP session with the remote agent.

if (!SnmpMgrClose(session))
{
printf("error on SnmpMgrClose %d\n", GetLastError());

return 1;
}
}

// Let the command interpreter know things went ok.

return 0;

} // end main()

以下是MAKEFILE文件

# Nmake macros for building Windows 32-Bit apps

TARGETOS=WINNT

!include <ntwin32.mak>

!if "$(CPU)" == "i386"
cflags = $(cflags) -D_CRTAPI1=_cdecl -D_CRTAPI2=_cdecl
!else
cflags = $(cflags) -D_CRTAPI1= -D_CRTAPI2=
!endif

all: snmputil.exe

snmputil.obj: snmputil.c
$(cc) $(cflags) $(cvars) $(cdebug) snmputil.c

snmputil.exe: snmputil.obj
$(link) $(linkdebug) $(conflags) -out:snmputil.exe snmputil.obj $(conlibsdll) \
advapi32.lib snmpapi.lib mgmtapi.lib
　
如果开始有链接错误，那么八成是因为需要加入mgmtapi.lib snmpapi.lib 这两个库文件到链接选项里。

运行这个程序生成snmputil.exe

2.3 运行
在命令模式下输入 snmputil get 你的IP地址或者用户名 public .1.3.6.1.2.1.1.1.0

是不是看到了你机器地相关信息。如果是网络上地其他机器，如果安装了SNMP，也可以看到他的信息。至于为什么什么用，就请您再接再厉地学习了。

以上内容为二手转帖；
我编译时遇到两个错误，我对编译器的使用不熟悉，希望得到各位大哥的指点。
如果我想学习使用编译器，应该看什么书。我不熟悉编译多个文件，也不知道 MAKEFILE 文件的作用和如何使用。
编译错误信息如下：
inking...
LIBCD.lib(wincrt0.obj) : error LNK2001: unresolved external symbol _WinMain@16
Debug/t.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

t.exe - 2 error(s), 0 warning(s)
Top

3 楼languagec（各有所求）回复于 2006-03-03 18:55:52 得分 0

由于帖子内容较长，从后往前看可能比较好
Top

4 楼jiangsheng（蒋晟.Net[MVP]）回复于 2006-03-04 09:50:40 得分 100

明显是目标平台错了，用基于Windows的程序的配置编译控制台程序
http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B131204Top

vc6.0 编译时出现两个问题（二手转帖）

1 楼languagec（各有所求）回复于 2006-03-03 18:53:58 得分 0

2 楼languagec（各有所求）回复于 2006-03-03 18:54:12 得分 0

3 楼languagec（各有所求）回复于 2006-03-03 18:55:52 得分 0

4 楼jiangsheng（蒋晟.Net[MVP]）回复于 2006-03-04 09:50:40 得分 100

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vc6.0 编译时出现两个问题 （ 二手转帖 ）

1 楼languagec（各有所求）回复于 2006-03-03 18:53:58 得分 0

2 楼languagec（各有所求）回复于 2006-03-03 18:54:12 得分 0

3 楼languagec（各有所求）回复于 2006-03-03 18:55:52 得分 0

4 楼jiangsheng（蒋晟.Net[MVP]）回复于 2006-03-04 09:50:40 得分 100

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vc6.0 编译时出现两个问题（二手转帖）