Question

在Debian中使用C程序，我需要访问一个在其末尾有数字的目录，偶尔会有变化。从命令提示符访问时，我可以选项卡完成或使用*，如何使用fopen或其他方法从C程序执行此操作？

pwm = fopen("/sys/devices/ocp.3/pwm_test_P8_19.15/duty // this is the changing directory
pwm = fopen("/sys/devices/ocp.3/pwm_t*/duty // this did not work

Answer 1

使用stdio.h，stdlib.h，unistd.h

int k = 0;
char pwm_path[100]; 
for (k = 14; k < 20; k++)
{

    sprintf( pwm_path, "/sys/devices/ocp.3/pwm_test_P8_19.%d/period", k );
    puts(pwm_path); //debug
    if (access( pwm_path, F_OK ) == 0) // if it finds path, then = 0
        {
        //printf("Files does exists, %d\n", k); // debug
        pwm = fopen( pwm_path, "w" );
        fseek(pwm,0,SEEK_SET);
        fprintf(pwm,"20000000"); // pulse period in uS
        fflush(pwm); // flush free up memory
        break; // break out of loop once found
        }
}

fopen自动完成更改目录

1 个答案: