SIGIO什么时候解雇？
我正在尝试接收串行数据，但是我无法确定时间。
当接收到串行数据时，什么时候SIGIO会触发-接收到数据的第一个字节时，还是当接收到特定字符（CR，NL ...）时？
设置串行数据端口：
/* Open serial port.
* O_RDONLY - Only receive data
* O_NOCTTY - Leave process control to other 'jobs' for better portability.
* O_NDELAY - Enable non-blocking read
*/
fd = open(PORT_PATHNAME, O_RDONLY | O_NOCTTY | O_NDELAY);
fd = open(PORT_PATHNAME, O_RDONLY | O_NOCTTY | O_NDELAY);
/* Set process ID, that will receive SIGIO signals for file desc. events */
fcntl (fd, F_SETOWN, getpid());
/* Enable generation of signals */
fcntl (fd, F_SETFL, O_ASYNC);
...
options.c_oflag &= ~OPOST;
/* Set terminal options using the file descriptor */
tcsetattr(fd, TCSANOW, &options);
struct termios options;
tcgetattr(fd, &options);
/* Set baudrate */
options.c_cflag = B115200;
设置信号中断：
/* Add UART handler function */
saio.sa_handler = signal_handler_IO;
/* Non-zero used for calling sighandler on alternative stacks and so on */
saio.sa_flags = 0;
/* Not specified by POSIX -> not in use */
saio.sa_restorer = NULL;
/* Bind SIGIO (async I/O signals) to the defined structure */
int status = sigaction(SIGIO, &saio, NULL);
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收到一字节数据后，SIGIO应该立即启动。
这是在带驱动程序的Linux上测试的最小示例ftdi_sio：
#include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <time.h> #include <unistd.h> #include <termios.h> #include <errno.h> #include <string.h> #include <sys/types.h> #include <sys/uio.h> #include <signal.h> #include <termios.h> #include <unistd.h> #define tty "/dev/ttyUSB0" #define baudrate B9600 void byteCallback(int status); // interrupt function int main(){ int ttyDev = open(tty, O_RDWR | O_NOCTTY | O_NONBLOCK); if (!ttyDev) { printf("couldn't open serial device"); return -1; } struct sigaction byteAction; // set the serial interrupt handler struct termios oldtio, newtio; //create signal handler byteAction.sa_handler = byteCallback; sigemptyset(&byteAction.sa_mask); //sa_mask = 0 byteAction.sa_flags = SA_RESTART; sigaction(SIGIO, &byteAction, NULL); //Allow process to detect SIGIO fcntl(ttyDev, F_SETOWN, getpid()); fcntl(ttyDev, F_SETFL, FASYNC); tcgetattr(ttyDev, &oldtio); //backup current settings newtio.c_cflag = baudrate | CS8 | CLOCAL | CREAD; newtio.c_cflag &= ~CRTSCTS; //disable hw flow control newtio.c_iflag &= ~(IXON | IXOFF | IXANY); //disable flow control newtio.c_iflag |= IGNPAR; //ignore parity newtio.c_oflag = 0; newtio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); //raw mode newtio.c_cc[VMIN] = 1; newtio.c_cc[VTIME] = 0; tcflush(ttyDev, TCIFLUSH); tcsetattr(ttyDev, TCSANOW, &newtio); while(1){ //Wait for SIGIO to fire } } void byteCallback(int status){ printf("SIGIO fired!\r\n"); }2020-01-06 16:28:48赞同 展开评论 打赏
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