ttyintf.cc Source File

00001 
00002 
00003 #include "ttyintf.hh"
00004 
00005 #include <stdio.h>
00006 #include <stdlib.h>
00007 
00008 #ifdef UNIX_LIKE_PLAT
00009 #ifndef UNIX
00010 #define UNIX 1
00011 #endif
00012 #endif
00013 
00014 #ifdef UNIX
00015 #include <errno.h>
00016 #include <string.h>
00017 #include <sys/types.h>
00018 #include <sys/stat.h>
00019 #include <fcntl.h>
00020 #include <unistd.h>
00021 #include <termios.h>
00022 #endif
00023 
00024 #ifdef WIN32
00025 #include <windows.h>
00026 #endif
00027 
00028 #include "rcs_prnt.hh"          // rcs_print_error()
00029 #include "linklist.hh"          // RCS_LINKED_LIST
00030 
00031 #ifdef UNIX
00032 typedef int RCS_SERIAL_PORT_HANDLE;
00033 #endif
00034 #ifdef WIN32
00035 typedef HANDLE RCS_SERIAL_PORT_HANDLE;
00036 #endif
00037 
00038 
00039 struct HANDLE_INFO
00040 {
00041   RCS_SERIAL_PORT_HANDLE handle;
00042   char name[256];
00043   int refcount;
00044 };
00045 
00046 RCS_LINKED_LIST *handles_list;
00047 
00048 
00049 HANDLE_INFO *
00050 findHandle (const char *name)
00051 {
00052   HANDLE_INFO *hi;
00053   if (NULL == handles_list)
00054     {
00055       return NULL;
00056     }
00057   hi = (HANDLE_INFO *) handles_list->get_head ();
00058   while (NULL != hi)
00059     {
00060       if (!strncmp (hi->name, name, 256))
00061         {
00062           return hi;
00063         }
00064     }
00065   return NULL;
00066 }
00067 
00068 void
00069 addHandle (const char *name, RCS_SERIAL_PORT_HANDLE _handle)
00070 {
00071   if (NULL == handles_list)
00072     {
00073       handles_list = new RCS_LINKED_LIST ();
00074     }
00075   HANDLE_INFO hi;
00076   strncpy (hi.name, name, 256);
00077   hi.refcount = 1;
00078   hi.handle = _handle;
00079   handles_list->store_at_tail (&hi, sizeof (HANDLE_INFO), 1);
00080 }
00081 
00082 
00083 int
00084 removeHandle (RCS_SERIAL_PORT_HANDLE _handle)
00085 {
00086   int refcount = 0;
00087   HANDLE_INFO *hi;
00088   if (NULL == handles_list)
00089     {
00090       return -1;
00091     }
00092   hi = (HANDLE_INFO *) handles_list->get_head ();
00093   while (NULL != hi)
00094     {
00095       if (hi->handle == _handle)
00096         {
00097           hi->refcount--;
00098           if (hi->refcount <= 0)
00099             {
00100               handles_list->delete_current_node ();
00101             }
00102           refcount = hi->refcount;
00103           break;
00104         }
00105     }
00106   if (handles_list->list_size <= 0)
00107     {
00108       delete handles_list;
00109       handles_list = NULL;
00110     }
00111   return refcount;
00112 }
00113 static char clean_string_buf[256];
00114 
00115 char *
00116 clean_string (char *string, int len)
00117 {
00118   int i = 0;
00119   char *cptr = string;
00120   char c = *cptr;
00121   if (len > 256)
00122     {
00123       len = 256;
00124     }
00125   while (i < len
00126          && (c == ' ' || c == '\t' || c == '=' || c == '\r' || c == '\n')
00127          && c != 0)
00128     {
00129       cptr++;
00130       c = *cptr;
00131       i++;
00132     }
00133   memset (clean_string_buf, 0, 256);
00134   if (c == 0 || i > len)
00135     {
00136       return clean_string_buf;
00137     }
00138   c = *cptr;
00139   char *dptr = clean_string_buf;
00140   while (i < len && c != 0 && c != ' ' && c != '\t' && c != '\r' && c != '\n')
00141     {
00142       *dptr = *cptr;
00143       cptr++;
00144       dptr++;
00145       i++;
00146       c = *cptr;
00147     }
00148   return clean_string_buf;
00149 }
00150 
00151 
00152 int
00153 print_serial_port_configuration (RCS_SERIAL_PORT_HANDLE _handle)
00154 {
00155 #ifdef UNIX
00156   int ttyFileFd = _handle;
00157   struct termios ttysettings;
00158   rcs_print ("tcgetattr returned %d\n", tcgetattr (ttyFileFd, &ttysettings));
00159   rcs_print ("c_iflag: %x ", ttysettings.c_iflag);
00160   if (ttysettings.c_iflag & BRKINT)
00161     rcs_print ("BRKINT ");
00162   if (ttysettings.c_iflag & ICRNL)
00163     rcs_print ("ICRNL ");
00164   if (ttysettings.c_iflag & IGNBRK)
00165     rcs_print ("IGNBRK ");
00166   if (ttysettings.c_iflag & IGNCR)
00167     rcs_print ("IGNCR ");
00168   if (ttysettings.c_iflag & IMAXBEL)
00169     rcs_print ("IMAXBEL ");
00170   if (ttysettings.c_iflag & INLCR)
00171     rcs_print ("INLCR ");
00172   if (ttysettings.c_iflag & INPCK)
00173     rcs_print ("INPCK ");
00174   if (ttysettings.c_iflag & IUCLC)
00175     rcs_print ("IUCLC ");
00176   if (ttysettings.c_iflag & IXANY)
00177     rcs_print ("IXANY ");
00178   if (ttysettings.c_iflag & IXOFF)
00179     rcs_print ("IXOFF ");
00180   if (ttysettings.c_iflag & IXON)
00181     rcs_print ("IXON ");
00182   if (ttysettings.c_iflag & PARMRK)
00183     rcs_print ("PARMRK ");
00184   rcs_print ("\n");
00185   rcs_print ("c_oflag: %x ", ttysettings.c_oflag);
00186   if (ttysettings.c_oflag & BSDLY)
00187     rcs_print ("BSDLY ");
00188   if (ttysettings.c_oflag & CRDLY)
00189     rcs_print ("CRDLY ");
00190   if (ttysettings.c_oflag & FFDLY)
00191     rcs_print ("FFDLY ");
00192   if (ttysettings.c_oflag & NLDLY)
00193     rcs_print ("NLDLY ");
00194   if (ttysettings.c_oflag & OCRNL)
00195     rcs_print ("OCRNL ");
00196   if (ttysettings.c_oflag & OFDEL)
00197     rcs_print ("OFDEL ");
00198   if (ttysettings.c_oflag & OFILL)
00199     rcs_print ("OFILL ");
00200   if (ttysettings.c_oflag & OLCUC)
00201     rcs_print ("OLCUC ");
00202   if (ttysettings.c_oflag & ONLCR)
00203     rcs_print ("ONLCR ");
00204   if (ttysettings.c_oflag & ONLRET)
00205     rcs_print ("ONLRET ");
00206   if (ttysettings.c_oflag & ONOCR)
00207     rcs_print ("ONOCR ");
00208 #ifdef ONEOT
00209   if (ttysettings.c_oflag & ONOEOT)
00210     rcs_print ("ONEOT ");
00211 #endif
00212   if (ttysettings.c_oflag & OPOST)
00213     rcs_print ("OPOST ");
00214 #ifdef OXTABS
00215   if (ttysettings.c_oflag & OXTABS)
00216     rcs_print ("OXTABS ");
00217 #endif
00218   if (ttysettings.c_oflag & TABDLY)
00219     rcs_print ("TABDLY ");
00220   if (ttysettings.c_oflag & VTDLY)
00221     rcs_print ("VTDLY ");
00222   rcs_print ("\n");
00223   rcs_print ("c_cflag: %x ", ttysettings.c_cflag);
00224 #ifdef CCTS_OFLOW
00225   if (ttysettings.c_cflag & CCTS_OFLOW)
00226     rcs_print ("CCTS_OFLOW ");
00227 #endif
00228 
00229 #ifdef CIGNORE
00230   if (ttysettings.c_cflag & CIGNORE)
00231     rcs_print ("CIGNORE ");
00232 #endif
00233 
00234   if (ttysettings.c_cflag & CLOCAL)
00235     rcs_print ("CLOCAL ");
00236   if (ttysettings.c_cflag & CREAD)
00237     rcs_print ("CREAD ");
00238 #ifdef CRTS_IFLOW
00239   if (ttysettings.c_cflag & CRTS_IFLOW)
00240     rcs_print ("CRTS_IFLOW ");
00241 #endif
00242   if ((ttysettings.c_cflag & CSIZE) == CS5)
00243     rcs_print ("CS5 ");
00244   if ((ttysettings.c_cflag & CSIZE) == CS6)
00245     rcs_print ("CS6 ");
00246   if ((ttysettings.c_cflag & CSIZE) == CS7)
00247     rcs_print ("CS7 ");
00248   if ((ttysettings.c_cflag & CSIZE) == CS8)
00249     rcs_print ("CS8 ");
00250   if (ttysettings.c_cflag & CSTOPB)
00251     rcs_print ("CSTOPB ");
00252   if (ttysettings.c_cflag & HUPCL)
00253     rcs_print ("HUPCL ");
00254 #ifdef MDMBUF
00255   if (ttysettings.c_cflag & MDMBUF)
00256     rcs_print ("MDMBUF ");
00257 #endif
00258   if (ttysettings.c_cflag & PARENB)
00259     rcs_print ("PARENB ");
00260   if (ttysettings.c_cflag & PARODD)
00261     rcs_print ("PARODD ");
00262   rcs_print ("\n");
00263   rcs_print ("c_lflag: %x ", ttysettings.c_lflag);
00264 #ifdef ALTWERASE
00265   if (ttysettings.c_cflag & ALTWERASE)
00266     rcs_print ("ALTWERASE ");
00267 #endif
00268   if (ttysettings.c_cflag & ECHO)
00269     rcs_print ("ECHO ");
00270   if (ttysettings.c_cflag & ECHOCTL)
00271     rcs_print ("ECHOCTL ");
00272   if (ttysettings.c_cflag & ECHOE)
00273     rcs_print ("ECHOE ");
00274   if (ttysettings.c_cflag & ECHOK)
00275     rcs_print ("ECHOK ");
00276   if (ttysettings.c_cflag & ECHOKE)
00277     rcs_print ("ECHOKE ");
00278   if (ttysettings.c_cflag & ECHONL)
00279     rcs_print ("ECHONL ");
00280   if (ttysettings.c_cflag & ECHOPRT)
00281     rcs_print ("ECHOPRT ");
00282   if (ttysettings.c_cflag & FLUSHO)
00283     rcs_print ("FLUSHO ");
00284   if (ttysettings.c_cflag & ICANON)
00285     rcs_print ("ICANON ");
00286   if (ttysettings.c_cflag & IEXTEN)
00287     rcs_print ("IEXTEN ");
00288   if (ttysettings.c_cflag & ISIG)
00289     rcs_print ("ISIG ");
00290   if (ttysettings.c_cflag & NOFLSH)
00291     rcs_print ("NOFLSH ");
00292 #ifdef NOKERNINFO
00293   if (ttysettings.c_cflag & NOKERNINFO)
00294     rcs_print ("NOKERNINFO ");
00295 #endif
00296   if (ttysettings.c_cflag & PENDIN)
00297     rcs_print ("PENDIN ");
00298   if (ttysettings.c_cflag & TOSTOP)
00299     rcs_print ("TOSTOP ");
00300   if (ttysettings.c_cflag & XCASE)
00301     rcs_print ("XCASE ");
00302   rcs_print ("\n");
00303 #endif
00304 
00305 #ifdef WIN32
00306   DCB dcb;
00307   if (!GetCommState (_handle, &dcb))
00308     {
00309       return -1;
00310     }
00311   rcs_print ("DCBlength=%d\n", dcb.DCBlength);  // sizeof(DCB)
00312   rcs_print ("BaudRate=%d\n", dcb.BaudRate);    // current baud rate
00313   rcs_print ("fBinary=%d\n", dcb.fBinary);      // binary mode, no EOF check
00314   rcs_print ("fParity=%d\n", dcb.fParity);      // enable parity checking
00315   rcs_print ("fOutxCtsFlow=%d\n", dcb.fOutxCtsFlow);    // CTS output flow control
00316   rcs_print ("fOutxDsrFlow=%d\n", dcb.fOutxDsrFlow);    // DSR output flow control
00317   rcs_print ("fDtrControl=%d\n", dcb.fDsrSensitivity);  // DTR flow control type
00318   rcs_print ("fDsrSensitivity=%d\n", dcb.fDsrSensitivity);      // DSR sensitivity
00319   rcs_print ("fTXContinueOnXoff=%d\n", dcb.fTXContinueOnXoff);  // XOFF continues Tx
00320   rcs_print ("fOutX=%d\n", dcb.fOutX);  // XON/XOFF out flow control
00321   rcs_print ("fInX=%d\n", dcb.fInX);    // XON/XOFF in flow control
00322   rcs_print ("fErrorChar=%d\n", dcb.fErrorChar);        // enable error replacement
00323   rcs_print ("fNull=%d\n", dcb.fNull);  // enable null stripping
00324   rcs_print ("fRtsControl=%d\n", dcb.fRtsControl);      // RTS flow control
00325   rcs_print ("fAbortOnError=%d\n", dcb.fAbortOnError);  // abort reads/writes on error
00326   rcs_print ("XonLim=%d\n", dcb.XonLim);        // transmit XON threshold
00327   rcs_print ("XoffLim=%d\n", dcb.XoffLim);      // transmit XOFF threshold
00328   rcs_print ("ByteSize=%d\n", dcb.ByteSize);    // number of bits/byte, 4-8
00329   rcs_print ("Parity=%d\n", dcb.Parity);        // 0-4=no,odd,even,mark,space
00330   rcs_print ("StopBits=%d\n", dcb.StopBits);    // 0,1,2 = 1, 1.5, 2
00331   rcs_print ("XonChar=%x %c\n", dcb.XoffChar, dcb.XoffChar);    // Tx and Rx XON character
00332   rcs_print ("XoffChar=%x %c\n", dcb.XoffChar, dcb.XoffChar);   // Tx and Rx XOFF character
00333   rcs_print ("ErrorChar=%x %c\n", dcb.ErrorChar, dcb.ErrorChar);        // error replacement character
00334   rcs_print ("EofChar=%x %c\n", dcb.EofChar, dcb.EofChar);      // end of input character
00335   rcs_print ("EvtChar=%x %c\n", dcb.EvtChar, dcb.EvtChar);      // received event character
00336 #endif
00337   return 0;
00338 }
00339 
00340 int
00341 set_serial_port_configuration (RCS_SERIAL_PORT_HANDLE _handle,
00342                                rcs_serial_port_setting * _settings)
00343 {
00344 #ifdef UNIX
00345   struct termios ttysettings;
00346   int ttyFileFd = _handle;
00347   if (tcgetattr (ttyFileFd, &ttysettings) < 0)
00348     {
00349       return -1;
00350     }
00351   ttysettings.c_iflag = 0;
00352   ttysettings.c_oflag = 0;
00353   ttysettings.c_cflag = CLOCAL | CREAD;
00354   if (NULL != _settings)
00355     {
00356       if (_settings->data_bits == 8)
00357         {
00358           ttysettings.c_cflag |= CS8;
00359         }
00360       else if (_settings->data_bits == 7)
00361         {
00362           ttysettings.c_cflag |= CS7;
00363         }
00364       if (_settings->use_parity)
00365         {
00366           ttysettings.c_cflag |= PARENB;
00367           if (!_settings->even_parity)
00368             {
00369               ttysettings.c_cflag |= PARODD;
00370             }
00371         }
00372     }
00373   ttysettings.c_lflag = 0;
00374   ttysettings.c_cc[VMIN] = 0;
00375   ttysettings.c_cc[VTIME] = 0;
00376   int cfsetting = B9600;
00377   if (NULL != _settings)
00378     {
00379       switch (_settings->baud_rate)
00380         {
00381 #ifdef B50
00382         case 50:
00383           cfsetting = B50;
00384           break;
00385 #endif
00386 
00387 #ifdef B75
00388         case 75:
00389           cfsetting = B75;
00390           break;
00391 #endif
00392 
00393 #ifdef B110
00394         case 110:
00395           cfsetting = B110;
00396           break;
00397 #endif
00398 
00399 #ifdef B150
00400         case 150:
00401           cfsetting = B150;
00402           break;
00403 #endif
00404 
00405 #ifdef B200
00406         case 200:
00407           cfsetting = B200;
00408           break;
00409 #endif
00410 
00411 #ifdef B300
00412         case 300:
00413           cfsetting = B300;
00414           break;
00415 #endif
00416 
00417 #ifdef B600
00418         case 600:
00419           cfsetting = B600;
00420           break;
00421 #endif
00422 
00423 #ifdef B1200
00424         case 1200:
00425           cfsetting = B1200;
00426           break;
00427 #endif
00428 
00429 #ifdef B1800
00430         case 1800:
00431           cfsetting = B1800;
00432           break;
00433 #endif
00434 
00435 #ifdef B2400
00436         case 2400:
00437           cfsetting = B2400;
00438           break;
00439 #endif
00440 
00441 #ifdef B4800
00442         case 4800:
00443           cfsetting = B4800;
00444           break;
00445 #endif
00446 
00447 #ifdef B9600
00448         case 9600:
00449           cfsetting = B9600;
00450           break;
00451 #endif
00452 
00453 
00454 #ifdef B19200
00455         case 19200:
00456           cfsetting = B19200;
00457           break;
00458 #endif
00459 
00460 
00461 #ifdef B38400
00462         case 38400:
00463           cfsetting = B38400;
00464           break;
00465 #endif
00466 
00467 
00468 #ifdef B57600
00469         case 57600:
00470           cfsetting = B57600;
00471           break;
00472 #endif
00473 
00474 
00475 #ifdef B76800
00476         case 76800:
00477           cfsetting = B76800;
00478           break;
00479 #endif
00480 
00481 
00482 #ifdef B115200
00483         case 115200:
00484           cfsetting = B115200;
00485           break;
00486 #endif
00487 
00488 
00489 #ifdef B153600
00490         case 153600:
00491           cfsetting = B153600;
00492           break;
00493 #endif
00494 
00495 
00496 #ifdef B230400
00497         case 230400:
00498           cfsetting = B230400;
00499           break;
00500 #endif
00501 
00502 
00503 #ifdef B307200
00504         case 307200:
00505           cfsetting = B307200;
00506           break;
00507 #endif
00508 
00509 #ifdef B460800
00510         case 460800:
00511           cfsetting = B460800;
00512           break;
00513 #endif
00514 
00515         default:
00516           rcs_print_error ("Invalid baud rate for serial port. (%d)\n",
00517                            _settings->baud_rate);
00518         }
00519     }
00520   if (cfsetospeed (&ttysettings, cfsetting) < 0)
00521     {
00522       rcs_print_error
00523         ("Can't set baud rate. cfsetospeed(*,%d): errno = %d %s\n", cfsetting,
00524          errno, strerror (errno));
00525       return -1;
00526     }
00527   if (cfsetispeed (&ttysettings, cfsetting) < 0)
00528     {
00529       rcs_print_error
00530         ("Can't set baud rate. cfsetospeed(*,%d): errno = %d %s\n", cfsetting,
00531          errno, strerror (errno));
00532       return -1;
00533     }
00534   if (tcsetattr (ttyFileFd, TCSANOW, &ttysettings) < 0)
00535     {
00536       rcs_print_error
00537         ("Can't set serial port attributes. tcsetattr: errno = %d %s\n",
00538          errno, strerror (errno));
00539       return -1;
00540     }
00541 #endif
00542 #ifdef WIN32
00543   DCB dcb;
00544   if (!GetCommState (_handle, &dcb))
00545     {
00546       rcs_print_sys_error (GETLASTERROR_ERROR_SOURCE,
00547                            "Can't GetCommState for a serial communications port.\n");
00548       return -1;
00549     }
00550   // initialize TTY info structure
00551   dcb.BaudRate = CBR_9600;
00552   if (NULL != _settings)
00553     {
00554       dcb.BaudRate = _settings->baud_rate;
00555     }
00556   dcb.fBinary = FALSE;
00557   dcb.fParity = NOPARITY;
00558   dcb.fOutxCtsFlow = FALSE;
00559   dcb.fOutxDsrFlow = FALSE;
00560   dcb.fDtrControl = DTR_CONTROL_DISABLE;
00561   dcb.fDsrSensitivity = FALSE;
00562   dcb.fTXContinueOnXoff = TRUE;
00563   dcb.fOutX = FALSE;
00564   dcb.fInX = FALSE;
00565   dcb.fErrorChar = FALSE;
00566   dcb.fNull = FALSE;
00567   dcb.fRtsControl = RTS_CONTROL_DISABLE;
00568   dcb.ByteSize = 8;
00569   dcb.Parity = NOPARITY;
00570   dcb.StopBits = ONESTOPBIT;
00571   if (NULL != _settings)
00572     {
00573       dcb.ByteSize = _settings->data_bits;
00574       if (!_settings->use_parity)
00575         {
00576           dcb.Parity = NOPARITY;
00577         }
00578       else
00579         {
00580           if (!_settings->even_parity)
00581             {
00582               dcb.Parity = ODDPARITY;
00583             }
00584           else
00585             {
00586               dcb.Parity = EVENPARITY;
00587             }
00588           dcb.fParity = TRUE;
00589         }
00590       if (_settings->stop_bits == 2)
00591         {
00592           dcb.StopBits = TWOSTOPBITS;
00593         }
00594     }
00595   if (!SetCommState (_handle, &dcb))
00596     {
00597       rcs_print_sys_error (GETLASTERROR_ERROR_SOURCE,
00598                            "Can't SetCommState for a serial communications port.\n");
00599       return -1;
00600     }
00601 #endif
00602   return 0;
00603 }
00604 
00605 
00606 RCS_SERIAL_PORT_HANDLE
00607 open_serial_communications_port (const char *name)
00608 {
00609   RCS_SERIAL_PORT_HANDLE rcs_handle;
00610   HANDLE_INFO *hi = findHandle (name);
00611   if (NULL != hi)
00612     {
00613       hi->refcount++;
00614       return hi->handle;
00615     }
00616 #ifdef UNIX
00617   int ttyFileFd = open (name, O_RDWR | O_NDELAY);
00618   if (ttyFileFd < 0)
00619     {
00620       rcs_print_error
00621         ("Can't open %s as a serial communications port. : %d %s\n", name,
00622          errno, strerror (errno));
00623       return ((RCS_SERIAL_PORT_HANDLE) - 1);
00624     }
00625   rcs_handle = ttyFileFd;
00626 #endif
00627 #ifdef WIN32
00628   HANDLE handle =
00629     CreateFile (name, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING,
00630                 FILE_FLAG_NO_BUFFERING, NULL);
00631   if (handle == INVALID_HANDLE_VALUE)
00632     {
00633       rcs_print_sys_error (GETLASTERROR_ERROR_SOURCE,
00634                            "Can't open %s as a serial communications port.\n",
00635                            name);
00636       return ((RCS_SERIAL_PORT_HANDLE) - 1);
00637     }
00638   rcs_handle = handle;
00639 #endif
00640   if (((int) rcs_handle) > 0)
00641     {
00642       addHandle (name, rcs_handle);
00643     }
00644   return rcs_handle;
00645 }
00646 
00647 
00648 int
00649 close_serial_communications_port (RCS_SERIAL_PORT_HANDLE _handle)
00650 {
00651   if (removeHandle (_handle))
00652     {
00653       return 0;
00654     }
00655 #ifdef UNIX
00656   return close (_handle);
00657 #endif
00658 #ifdef WIN32
00659   return CloseHandle (_handle);
00660 #endif
00661 }
00662 
00663 
00664 int
00665 read_serial_communications_port (RCS_SERIAL_PORT_HANDLE _handle, char *buf,
00666                                  int maxlen)
00667 {
00668 #ifdef UNIX
00669   int ttyFileFd = _handle;
00670   int bytes_read = read (ttyFileFd, buf, maxlen);
00671   return bytes_read;
00672 #endif
00673 #ifdef WIN32
00674   unsigned long bytes_read = 0;
00675   if (!ReadFile (_handle, buf, maxlen, &bytes_read, NULL))
00676     {
00677       rcs_print_sys_error (GETLASTERROR_ERROR_SOURCE,
00678                            "Can't read from a serial communications port.\n");
00679       return -1;
00680     }
00681   return bytes_read;
00682 #endif
00683 }
00684 
00685 
00686 int
00687 readn_serial_communications_port (RCS_SERIAL_PORT_HANDLE _handle, char *buf,
00688                                   int len)
00689 {
00690   int bytes_read = 0;
00691   while (bytes_read < len)
00692     {
00693       int rval = read_serial_communications_port (_handle, buf + bytes_read,
00694                                                   len - bytes_read);
00695       if (rval < 0)
00696         {
00697           return rval;
00698         }
00699       bytes_read += rval;
00700     }
00701   return bytes_read;
00702 }
00703 
00704 int
00705 write_serial_communications_port (RCS_SERIAL_PORT_HANDLE _handle, char *buf,
00706                                   int maxlen)
00707 {
00708 #ifdef UNIX
00709   int ttyFileFd = _handle;
00710   return write (ttyFileFd, buf, maxlen);
00711 #endif
00712 #ifdef WIN32
00713   unsigned long bytes_written = 0;
00714   if (!WriteFile (_handle, buf, maxlen, &bytes_written, NULL))
00715     {
00716       rcs_print_sys_error (GETLASTERROR_ERROR_SOURCE,
00717                            "Can't write to a serial communications port.\n");
00718       return -1;
00719     }
00720   return bytes_written;
00721 #endif
00722 }