endpwent¶

Synopsis¶

#include <pwd.h>

void endpwent(void);

struct passwd *getpwent(void);

void setpwent(void);

Status¶

Implemented

Conformance¶

IEEE Std 1003.1-2017

Description¶

These functions shall retrieve information about users.

The getpwent() function shall return a pointer to a structure containing the broken-out fields of an entry in the user database. Each entry in the user database contains a passwd structure. If the user database is not already open, getpwent() shall open it and return a pointer to a passwd structure containing the first entry in the database. Thereafter, it shall return a pointer to a passwd structure containing the next entry in the user database. Successive calls can be used to search the entire user database. The user database is the /etc/passwd file.

If an end-of-file or an error is encountered on reading, getpwent() shall return a null pointer.

The setpwent() function shall rewind the user database so that the next getpwent() call returns the first entry, allowing repeated searches.

The endpwent() function shall close the user database.

The setpwent() and endpwent() functions shall not change the setting of errno if successful.

On error, the setpwent() and endpwent() functions shall set errno to indicate the error.

Since no value is returned by the setpwent() and endpwent() functions, an application wishing to check for error situations should set errno to 0, then call the function, then check errno.

These functions need not be thread-safe.

Return value¶

On successful completion, getpwent() shall return a pointer to a passwd structure. On end-of-file, getpwent() shall return a null pointer and shall not change the setting of errno. On error, getpwent() shall return a null pointer and errno shall be set to indicate the error.

The application shall not modify the structure to which the return value points, nor any storage areas pointed to by pointers within the structure. The returned pointer, and pointers within the structure, might be invalidated or the structure or the storage areas might be overwritten by a subsequent call to getpwuid(), getpwnam(), or getpwent(). The returned pointer, and pointers within the structure, might also be invalidated if the calling thread is terminated.

Errors¶

These functions may fail if:

EINTR - A signal was caught during the operation.
EIO - An I/O error has occurred.

In addition, getpwent() and setpwent() may fail if:

EMFILE - All file descriptors available to the process are currently open.
ENFILE - The maximum allowable number of files is currently open in the system.

POSIX deviations¶

No POSIX deviations discovered.