我想了解使用dup2和dup.
从手册页:
DESCRIPTION
dup and dup2 create a copy of the file descriptor oldfd.
After successful return of dup or dup2, the old and new descriptors may
be used interchangeably. They share locks, file position pointers and
flags; for example, if the file position is modified by using lseek on
one of the descriptors, the position is also changed for the other.
The two descriptors do not share the close-on-exec flag, however.
dup uses the lowest-numbered …