混合fdopen()和open() - >坏文件描述符

Question

int source = open("hi", O_CREAT | O_RDONLY);
int dest = open("resultfile", O_CREAT | O_RDWR | O_TRUNC);

FILE* source1 = fdopen(source, "r");  
FILE* dest1 = fdopen(dest, "w+");

// outside of a testcase I would write something into 'resultfile' here

close(source);
close(dest);
fclose(source1);
fclose(dest1);

int sourcef = open("resultfile", O_RDONLY);
printf(strerror(errno)); // <--- Bad file descriptor

我不明白为什么？如何成功地将基于流的IO与open()混合使用？

我正在使用的库只接受一个整数fd(并且库在内部负责关闭它,可能是close()),但我仍然需要使用该文件,我不知道它是怎么回事没有像(fread(),ftell()等f()调用那样正确的可能

Answer 1

fclose呼唤close你.如果你想在调用后保持fd fclose,dupfd首先.

int fd = open(...);
int fd2 = dup(fd);
FILE *fp = fdopen(fd2);
fclose(fp);
// fd is still valid.

示例中的错误文件描述符错误消息从fclose(dest1)调用中延迟.