Write fault error writing device COM1

[linuxnow]

#include <stdio.h>

int main(void)
{
/* redirect standard output to a file */
if (freopen("COM1", "w", stdout) == NULL)
fprintf(stderr, "error redirecting stdout\n");
/* this output will go to a file */
printf("This will go into COM1.");

/* close the standard output stream */
fclose(stdout);

return 0;
}


TC 3中编译后运行
D:\C\TEMP>redirect

Write fault error writing device COM1
Abort, Retry, Ignore, Fail?
什么原因？