gsm - output of AT command c++ code -

i wrote following code sends simple message mobile gsm sm5100b. not work. check outputs of each printf line c++ code. example

at+cmfg=1 ok at+cmgs="69******" ok 

etc. there why implement this?

my code

#include <stdio.h> // standard input / output functions #include <string.h> // string function definitions #include <unistd.h> // unix standard function definitions #include <fcntl.h> // file control definitions #include <errno.h> // error number definitions #include <termios.h> // posix terminal control definitionss #include <time.h>   // time calls  int open_port(void) { int fd; // file description serial port fd = open("/dev/ttyama0", o_rdwr | o_noctty | o_ndelay); if(fd == -1) // if open unsucessful {     printf("open_port: unable open /dev/ttyama0. \n"); } else {     fcntl(fd, f_setfl, 0);     printf("port open.\n"); }  return(fd); } //open_port  int configure_port(int fd)      // configure port { struct termios port_settings;      // structure store port settings in  cfsetispeed(&port_settings, b9600);    // set baud rates cfsetospeed(&port_settings, b9600);  port_settings.c_cflag &= ~parenb;    // set no parity, stop bits, data bits port_settings.c_cflag &= ~cstopb; port_settings.c_cflag &= ~csize; port_settings.c_cflag |= cs8;  tcsetattr(fd, tcsanow, &port_settings);    // apply settings port return(fd);  }    void init_gsm() {  printf("at+cmgf=1\r\n");  sleep(3);  printf("at+cmgs=\"+34603****\"\r\n");  sleep(3);  //printf("hello\r\n%c",26);   printf("hello\x1a");  sleep(3); // printf("\x1a");  } int main(void) { int fd = open_port(); configure_port(fd); sleep(5); //query_modem(fd);     init_gsm(); return(0);  } 

most seriously, not waiting final result code after sending @ command. using sleep not valid solution. must fix proper parsing of response modem. see following answers more details, answer 1, answer 2.

then init_gsm function ought have int fd argument use sending @ commands reading response from.