dup2

函数名: dup2

功 能: 复制文件句柄

用 法: int dup2(int oldhandle, int newhandle);

程序例:

#include <sysstat.h>

#include <string.h>

#include <fcntl.h>

#include <io.h>

int main(void)

{

#define STDOUT 1

int nul, oldstdout;

char msg[] = "This is a test";

/* create a file */

nul = open("DUMMY.FIL", O_CREAT | O_RDWR,

S_IREAD | S_IWRITE);

/* create a duplicate handle for standard

output */

oldstdout = dup(STDOUT);

/*

redirect standard output to DUMMY.FIL

by duplicating the file handle onto the

file handle for standard output.

*/

dup2(nul, STDOUT);

/* close the handle for DUMMY.FIL */

close(nul);

/* will be redirected into DUMMY.FIL */

write(STDOUT, msg, strlen(msg));

/* restore original standard output

handle */

dup2(oldstdout, STDOUT);

/* close duplicate handle for STDOUT */

close(oldstdout);

return 0;

}