void serial_read(int fd, char *buffer, size_t buf_size) ssize_t n = read(fd, buffer, buf_size - 1); if (n < 0) perror("read"); else if (n > 0) buffer[n] = '\0'; printf("Read %ld bytes: %s\n", n, buffer);
void serial_write(int fd, const char *data, size_t len) ssize_t written = write(fd, data, len); if (written < 0) perror("write"); else printf("Wrote %ld bytes\n", written);
Here’s a practical for serial port communication on Linux/POSIX systems. It demonstrates opening, configuring, reading, writing, and closing a serial port. Serial Port Communication in C – Complete Example #include <stdio.h> // Standard I/O #include <stdlib.h> // Exit functions #include <fcntl.h> // File control (open) #include <termios.h> // Terminal I/O (serial config) #include <unistd.h> // POSIX (read, write, close) #include <string.h> // String operations int serial_open(const char *device, speed_t baud) IGNCR); // No newline conversions
printf("Serial port %s opened at 115200 baud\n", device); serial port c example
// VMIN = 1, VTIME = 0 -> blocking read until at least 1 char tty.c_cc[VMIN] = 1; tty.c_cc[VTIME] = 0;
// Apply attributes if (tcsetattr(fd, TCSANOW, &tty) != 0) perror("tcsetattr"); close(fd); return -1;
int fd = serial_open(device, baud); if (fd < 0) return EXIT_FAILURE; void serial_read(int fd
int main() const char *device = "/dev/ttyUSB0"; // Change to your port speed_t baud = B115200;
// Wait for response char response[256]; serial_read(fd, response, sizeof(response));
// Send a command const char *cmd = "AT\r\n"; serial_write(fd, cmd, strlen(cmd)); size_t buf_size) ssize_t n = read(fd
// Clean up close(fd); return EXIT_SUCCESS; Compile with:
// Raw output mode tty.c_oflag &= ~OPOST;