PW_DUP(3) | Library Functions Manual | PW_DUP(3) |
pw_dup
— make a
copy of a struct passwd
#include
<pwd.h>
struct passwd *
pw_dup
(const
struct passwd *pw);
The
pw_dup
()
function allocates sufficient memory for a copy of the struct passwd
pw, does the copy, and returns a pointer to it. This
is useful as subsequent calls to
getpwent
(),
getpwnam
(),
and
getpwuid
()
will overwrite the data they returned from previous calls.
The returned pointer should be deallocated by a
single call to free(3). Since
pw_dup
()
allocates space for the copy in one chunk, it is not necessary to free the
individual strings contained in the returned struct passwd.
If insufficient memory is available, NULL
is returned.
The following will make a copy of the struct passwd for root and store it in "pw_save":
struct passwd *pw, *pw_save; if ((pw = getpwnam("root")) == NULL) { fprintf(stderr, "Cannot find root in the password file.\n"); exit(1); } if ((pw_save = pw_dup(pw)) == NULL) { fprintf(stderr, "Out of memory.\n"); exit(1); }
pw_dup
() function may fail and set the
external variable errno for any of the errors
specified for the library function
malloc(3).
The pw_dup
() function first appeared in
OpenBSD 2.9.
January 25, 2019 | OpenBSD-current |