github.com/afumu/libc@v0.0.6/musl/src/unistd/dup3.c (about)

     1  #define _GNU_SOURCE
     2  #include <unistd.h>
     3  #include <errno.h>
     4  #include <fcntl.h>
     5  #include "syscall.h"
     6  
     7  int __dup3(int old, int new, int flags)
     8  {
     9  	int r;
    10  #ifdef SYS_dup2
    11  	if (old==new) return __syscall_ret(-EINVAL);
    12  	if (flags & O_CLOEXEC) {
    13  		while ((r=__syscall(SYS_dup3, old, new, flags))==-EBUSY);
    14  		if (r!=-ENOSYS) return __syscall_ret(r);
    15  	}
    16  	while ((r=__syscall(SYS_dup2, old, new))==-EBUSY);
    17  	if (flags & O_CLOEXEC) __syscall(SYS_fcntl, new, F_SETFD, FD_CLOEXEC);
    18  #else
    19  	while ((r=__syscall(SYS_dup3, old, new, flags))==-EBUSY);
    20  #endif
    21  	return __syscall_ret(r);
    22  }
    23  
    24  weak_alias(__dup3, dup3);