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我是编程新手，在使用串行 API 连接同步链接适配器的示例 C 代码时遇到问题。
我正在尝试使用 C++ 编译器 (Visual Studio C++ 2010) 编译 C 源文件。我更改了 C++ 编译器的设置以将项目编译为 C(在项目属性页下 -> C/C++ -> 高级)，并包括附加目录 mghdlc.h 和链接 mghdlc.lib(在链接器下 -> 附加)库目录)。代码如下:
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <windows.h>
#include <errno.h>
#include <mghdlc.h>
int get_port_id(char *name)
{
unsigned long i, rc, count;
int port_id = 0;
PMGSL_PORT ports;
/* get count of available ports */
rc = MgslEnumeratePorts(NULL, 0, &count);
if (rc != NO_ERROR) {
printf("MgslEnumeratePorts() error=%d\n", rc);
return 0;
}
if (!count)
return 0;
/* allocate memory to hold port information */
ports = malloc(count * sizeof(MGSL_PORT));
if (ports == NULL) {
printf("memory allocation failed\n");
return 0;
}
/* get port information */
rc = MgslEnumeratePorts(ports, count * sizeof(MGSL_PORT), &count);
if (rc != NO_ERROR) {
printf("MgslEnumeratePorts() error=%d\n", rc);
goto done;
}
/* search for entry with matching name */
for (i=0; i < count; i++) {
if (!_stricmp(ports[i].DeviceName, name)) {
port_id = ports[i].PortID;
break;
}
}
done:
free(ports);
return port_id;
}
int stop_program = 0;
void sigint_handler(int sigid)
{
stop_program = 1;
}
int main(int argc, char **argv)
{
int port_id;
HANDLE fd;
FILE *fp;
DWORD rc;
int databuf_size;
int count;
int written;
OVERLAPPED ol;
MGSL_RECEIVE_REQUEST *rx_req;
MGSL_PARAMS params;
if (argc < 2) {
printf("\nYou must specify device name as argument.\n"
"Examples:\n"
"C:>receive-raw MGMP4P2 (adapter #4 port #2 of multiport adapter)\n"
"C:>receive-raw MGHDLC1 (single port adapter adapter #1)\n"
"Available device names can be viewed in the SyncLink branch\n"
"of the Windows device manager.\n\n");
return 1;
}
printf("receive raw data on %s\n", argv[1]);
/* convert device name to port ID */
port_id = get_port_id(argv[1]);
if (port_id == 0) {
printf("No such port %s\n", argv[1]);
return 1;
}
/* open device */
rc = MgslOpen(port_id, &fd);
if (rc != NO_ERROR) {
printf("MgslOpen error=%d\n", rc);
return rc;
}
/* open file to store received data */
fp = fopen("data", "wb");
if (fp == NULL) {
printf("fopen error=%d %s\n", errno, strerror(errno));
return errno;
}
//#define SET_BASE_CLOCK 1
#ifdef SET_BASE_CLOCK
/*
* Set base clock frequency if custom hardware base clock installed.
*
* Use only if a base clock different than the standard 14745600
* is installed at the factory. The driver uses this value to
* calculate data clock rates which are derived from the base clock.
*/
rc = MgslSetOption(fd, MGSL_OPT_CLOCK_BASE_FREQ, 25000000);
if (rc != NO_ERROR)
printf("MgslSetOption(MGSL_OPT_CLOCK_BASE_FREQ) error=%d\n", rc);
#endif
/* get current device parameters */
rc = MgslGetParams(fd, ¶ms);
if (rc != NO_ERROR) {
printf("MgslGetParams() error=%d\n", rc);
return rc;
}
/*
* configure port for raw synchronous mode
* loopback disabled
* receiver clock source = RxC clock input
* transmit clock source = TxC clock input
* encoding = NRZ
* output clock on AUXCLK output at 19200 bps
* disable ITU/CCITT CRC-16 frame checking (not supported in raw mode)
*/
params.Mode = MGSL_MODE_RAW;
params.Loopback = 0;
params.Flags = HDLC_FLAG_RXC_RXCPIN + HDLC_FLAG_TXC_TXCPIN;
params.Encoding = HDLC_ENCODING_NRZ;
params.ClockSpeed = 19200;
params.CrcType = HDLC_CRC_NONE;
/* set current device parameters */
rc = MgslSetParams(fd, ¶ms);
if (rc != NO_ERROR) {
printf("MgslSetParams() error=%d\n", rc);
return rc;
}
/* set transmit idle pattern */
rc = MgslSetIdleMode(fd, HDLC_TXIDLE_ONES);
if (rc != NO_ERROR)
printf("MgslSetIdleMode() error=%d", rc);
printf("Turn on RTS and DTR serial outputs\n");
rc = MgslSetSerialSignals(fd, SerialSignal_RTS + SerialSignal_DTR);
if (rc != NO_ERROR)
printf("assert DTR/RTS error=%d\n", rc);
/* MgslReceive requires OVERLAPPED structure and event */
ol.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (ol.hEvent == NULL) {
printf("CreateEvent error = %d\n", GetLastError());
return 1;
}
/* MgslReceive needs MGSL_RECEIVE_REQUEST structure (header + data buffer) */
databuf_size = 128;
rx_req = malloc(sizeof(MGSL_RECEIVE_REQUEST) + databuf_size);
if (rx_req == NULL) {
printf("can't allocate receive request structure\n");
return 1;
}
MgslEnableReceiver(fd, 1); /* enable receiver */
signal(SIGINT, sigint_handler);
printf("press Ctrl-C to stop program\n");
while (!stop_program) {
/* prepare for MgslReceive call */
rx_req->DataLength = databuf_size;
ResetEvent(ol.hEvent);
rc = MgslReceive(fd, rx_req, &ol);
if (rc == ERROR_IO_PENDING) {
printf("wait for received data...");
while (!stop_program) {
rc = WaitForSingleObject(ol.hEvent, 100);
if (rc == WAIT_OBJECT_0)
break; /* receive request complete */
if (rc != WAIT_TIMEOUT) {
printf("WaitForSingleObject error = %d\n", GetLastError());
return rc;
}
}
if (stop_program) {
printf("Ctrl-C pressed, cancel receive request\n");
MgslCancelReceive(fd);
break;
}
} else if (rc != NO_ERROR) {
printf("MgslReceive error=%d\n", rc);
return rc;
}
/* process completed receive request */
if (rx_req->Status == RxStatus_OK) {
count = rx_req->DataLength;
printf("received %d bytes\n", count);
/* write received data to file */
written = (int)fwrite(rx_req->DataBuffer, sizeof(char), count, fp);
if (written != count)
printf("fwrite error=%d %s\n", errno, strerror(errno));
fflush(fp);
} else
printf("receive error, status = %d\n", rx_req->Status);
}
MgslEnableReceiver(fd, 0); /* disable receiver */
printf("Turn off RTS and DTR ser`enter code here`ial outputs\n");
rc = MgslSetSerialSignals(fd, 0);
if (rc != NO_ERROR)
printf("turn off DTR/RTS error=%d\n", rc);
MgslClose(fd); /* close device */
fclose(fp); /* close output file */
return 0;
}
但我得到以下错误:
1>------ Build started: Project: testing, Configuration: Debug Win32 ------
1> testing.cpp
1>c:\users\jjteo\documents\visual studio 2010\projects\testing\testing\testing.cpp(124): warning C4996: 'fopen': This function or variable may be unsafe. Consider using fopen_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\stdio.h(234) : see declaration of 'fopen'
1>c:\users\jjteo\documents\visual studio 2010\projects\testing\testing\testing.cpp(126): warning C4996: 'strerror': This function or variable may be unsafe. Consider using strerror_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\string.h(157) : see declaration of 'strerror'
1>c:\users\jjteo\documents\visual studio 2010\projects\testing\testing\testing.cpp(241): warning C4996: 'strerror': This function or variable may be unsafe. Consider using strerror_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\string.h(157) : see declaration of 'strerror'
1>testing.obj : error LNK2019: unresolved external symbol _MgslEnumeratePorts@12 referenced in function _get_port_id
1>testing.obj : error LNK2019: unresolved external symbol _MgslClose@4 referenced in function _main
1>testing.obj : error LNK2019: unresolved external symbol _MgslCancelReceive@4 referenced in function _main
1>testing.obj : error LNK2019: unresolved external symbol _MgslReceive@12 referenced in function _main
1>testing.obj : error LNK2019: unresolved external symbol _MgslEnableReceiver@8 referenced in function _main
1>testing.obj : error LNK2019: unresolved external symbol _MgslSetSerialSignals@8 referenced in function _main
1>testing.obj : error LNK2019: unresolved external symbol _MgslSetIdleMode@8 referenced in function _main
1>testing.obj : error LNK2019: unresolved external symbol _MgslSetParams@8 referenced in function _main
1>testing.obj : error LNK2019: unresolved external symbol _MgslGetParams@8 referenced in function _main
1>testing.obj : error LNK2019: unresolved external symbol _MgslOpen@8 referenced in function _main
1>c:\users\jjteo\documents\visual studio 2010\Projects\testing\Debug\testing.exe : fatal error LNK1120: 10 unresolved externals
========== 构建:0 成功，1 失败，0 最新，0 跳过 ==========
是不是用C++编译器编译c代码导致的问题？我该如何解决。谢谢。