串口读取的问题(问题解决高分相送 100分)__current_include_unsigned_lenth_time_out_comm_

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串口读取的问题(问题解决高分相送 100分)

来源: 互联网发布时间：2015-08-24

本文导语: 我写了一个读取串口的程序,但是每次读取的类容都是不完整的. 如果我让程序sleep(1)读取的内容又会多. 怎样控制读取才能取得自己想要的完整信息. | 用select监听,一次读取一个直到read返回0即...

我写了一个读取串口的程序,但是每次读取的类容都是不完整的.
如果我让程序sleep(1)读取的内容又会多.
怎样控制读取才能取得自己想要的完整信息.

用select监听,一次读取一个直到read返回0即可.

# include
# include
# include
# include
# include
# include
# include
# include
# include "tools.h"

extern  int comm_flag;
jmp_buf  env_buf;
void timeout_handler ( int );

FILE * fppp;

int rcv ( fd_r, fd_w, buffer, max_count )

unsigned char * buffer;
unsigned max_count;
int fd_r, fd_w;

{

unsigned char  * current, lrc;
unsigned int   i, lenth , time_out_comm;
char filename [ 80 ];
char date [ 9 ] , time [ 9 ] , tmp [40];

signal ( SIGALRM, timeout_handler );
alarm ( 0 );
setjmp ( env_buf );

current = buffer;
* current = 0x00;

if ( comm_flag == 1 ) {               /* modem pool need handshake */

while ( * current != 0x05 )   /** ENQ **/
read ( fd_r, current, 1 );

* current = 0x06;       /** ACK **/
write ( fd_w, current, 1 );

for ( i = 0; i = 6 )
return ( -1 );
}
else {       /* nac or rs232 */
while ( * current != 0x02 )   /**** STX ****/
   read ( fd_r, current, 1 );
}

/*
*  when recv time large 3 sec
*  error and exit !
*/
time_out_comm = GetTimeOut ( "COMPOS" ) ;
alarm ( time_out_comm ) ;

current ++;
for ( i = 0; i > 4 ) * 10 + ( * current & 0x0f );
current --;
lenth += ( * current >> 4 ) * 1000 + ( * current & 0x0f ) * 100;

current += 2;

ErrorLog ( TRACE, "lenth = %d", lenth );

if ( lenth >= 512 ) {

* current = 0x0;

alarm ( 0 ) ;

return ( -1 ) ;
}

for ( i = 0; i