linux - C代码中的段错误

Question

我昨天写了一个C 代码，运行良好。现在我想在文件中做一些更改，所以我只是将这段代码复制到一个新文件中。新文件的编译很好，但是当我尝试运行我的可执行文件时，我遇到了 segmentation fault。但是我以前的代码正在运行。最初我认为这是一个权限问题，所以我使用 chmod 777 更改了可执行文件的权限。但我仍然遇到 segmentation fault。这是我的代码:-

#include <stdio.h>
#include <time.h>
void pauseSec(int sec);
int main() {
        FILE *io,*iodir,*ioval,*iodir_S,*ioval_S,*io_S,*iodir_P,*ioval_P,*io_P;

        io = fopen("/sys/class/gpio/export", "w");
        fseek(io,0,SEEK_SET);
        fprintf(io,"%d",15);
        fflush(io);
        iodir = fopen("/sys/class/gpio/gpio15/direction", "w");
        fseek(iodir,0,SEEK_SET);
        fprintf(iodir,"out");
        fflush(iodir);
        while(1)
        {
                fprintf(ioval,"%d",1);
                fflush(ioval);
                pauseSec(1);
                fprintf(ioval,"%d",0);
                fflush(ioval);
                pauseSec(1);
        }
        fclose(io);
        fclose(iodir);
        fclose(ioval);
        return 0;
}
void pauseSec(int sec) {
        time_t now,later;
        now = time(NULL);
        later = time(NULL);
        while((later - now) < (double)sec)
        later = time(NULL);
}

我想知道为什么在两个不同的文件中编写相同的代码时表现不同。这可能是什么原因？

Answer 1

问题来了，忘记初始化 ioval。正确的代码在这里:-

#include <stdio.h>
#include <time.h>
void pauseSec(int sec);
int main() {
        FILE *io,*iodir,*ioval,*iodir_S,*ioval_S,*io_S,*iodir_P,*ioval_P,*io_P;

        io = fopen("/sys/class/gpio/export", "w");
        fseek(io,0,SEEK_SET);
        fprintf(io,"%d",15);
        fflush(io);

        iodir = fopen("/sys/class/gpio/gpio15/direction", "w");
        fseek(iodir,0,SEEK_SET);
        fprintf(iodir,"out");
        fflush(iodir);

        ioval = fopen("/sys/class/gpio/gpio15/value", "w");

        while(1)
        {
                fprintf(ioval,"%d",1);
                fflush(ioval);
                pauseSec(1);
                fprintf(ioval,"%d",0);
                fflush(ioval);
                pauseSec(1);
        }
        fclose(io);
        fclose(iodir);
        fclose(ioval);
        return 0;
}
void pauseSec(int sec) {
        time_t now,later;
        now = time(NULL);
        later = time(NULL);
        while((later - now) < (double)sec)
        later = time(NULL);
}