---
name: "getpwent_r"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/getpwent_r"
---

# getpwent\_r(3)

get passwd file entry reentrantly

## NAME

getpwent\_r, fgetpwent\_r - get passwd file entry reentrantly

## LIBRARY

Standard C library (*libc*, *-lc*)

## SYNOPSIS

```
#include <pwd.h>
```

**int getpwent\_r(**size\_t size;                **struct passwd \*restrict** *pwbuf***,**                **char** *buf***\[restrict** *size***\], size\_t** *size***,**                **struct passwd \*\*restrict** *pwbufp***);** **int fgetpwent\_r(**size\_t size;                **FILE \*restrict** *stream***, struct passwd \*restrict** *pwbuf***,**                **char** *buf***\[restrict** *size***\], size\_t** *size***,**                **struct passwd \*\*restrict** *pwbufp***);**

Feature Test Macro Requirements for glibc (see [**feature\_test\_macros**(7)](/feature_test_macros/7.md)):

**getpwent\_r**(),

```
    Since glibc 2.19:
        _DEFAULT_SOURCE
    glibc 2.19 and earlier:
        _BSD_SOURCE || _SVID_SOURCE
```

**fgetpwent\_r**():

```
    Since glibc 2.19:
        _DEFAULT_SOURCE
    glibc 2.19 and earlier:
        _SVID_SOURCE
```

## DESCRIPTION

The functions **getpwent\_r**() and **fgetpwent\_r**() are the reentrant versions of [**getpwent**(3)](/getpwent/3.md) and [**fgetpwent**(3)](/fgetpwent/3.md). The former reads the next passwd entry from the stream initialized by [**setpwent**(3)](/setpwent/3.md). The latter reads the next passwd entry from *stream*.

The *passwd* structure is defined in *\<pwd.h\>* as follows:

```
struct passwd {
    char    *pw_name;      /* username */
    char    *pw_passwd;    /* user password */
    uid_t    pw_uid;       /* user ID */
    gid_t    pw_gid;       /* group ID */
    char    *pw_gecos;     /* user information */
    char    *pw_dir;       /* home directory */
    char    *pw_shell;     /* shell program */
};
```

For more information about the fields of this structure, see [**passwd**(5)](/passwd/5.md).

The nonreentrant functions return a pointer to static storage, where this static storage contains further pointers to user name, password, gecos field, home directory and shell. The reentrant functions described here return all of that in caller-provided buffers. First of all there is the buffer *pwbuf* that can hold a *struct passwd*. And next the buffer *buf* of size *size* that can hold additional strings. The result of these functions, the *struct passwd* read from the stream, is stored in the provided buffer *\*pwbuf*, and a pointer to this *struct passwd* is returned in *\*pwbufp*.

## RETURN VALUE

On success, these functions return 0 and *\*pwbufp* is a pointer to the *struct passwd*. On error, these functions return an error value and *\*pwbufp* is NULL.

## ERRORS

- **ENOENT**

  No more entries.

- **ERANGE**

  Insufficient buffer space supplied. Try again with larger buffer.

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **getpwent\_r**() | Thread safety | MT-Unsafe race:pwent locale |
| **fgetpwent\_r**() | Thread safety | MT-Safe |

In the above table, *pwent* in *race:pwent* signifies that if any of the functions **setpwent**(), **getpwent**(), **endpwent**(), or **getpwent\_r**() are used in parallel in different threads of a program, then data races could occur.

## VERSIONS

Other systems use the prototype

```
struct passwd *
getpwent_r(struct passwd *pwd, char buf[.size], int size);
```

or, better,

```
int
getpwent_r(struct passwd *pwd, char buf[.size], int size,
           FILE **pw_fp);
```

## STANDARDS

None.

## HISTORY

These functions are done in a style resembling the POSIX version of functions like [**getpwnam\_r**(3)](/getpwnam_r/3.md).

## NOTES

The function **getpwent\_r**() is not really reentrant since it shares the reading position in the stream with all other threads.

## EXAMPLES

```
#define _GNU_SOURCE
#include <pwd.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#define BUFLEN 4096
int
main(void)
{
    struct passwd pw;
    struct passwd *pwp;
    char buf[BUFLEN];
    int i;
    setpwent();
    for (;;) {
        i = getpwent_r(&pw, buf, sizeof(buf), &pwp);
        if (i)
            break;
        printf("%s (%jd)\tHOME %s\tSHELL %s\n", pwp->pw_name,
               (intmax_t) pwp->pw_uid, pwp->pw_dir, pwp->pw_shell);
    }
    endpwent();
    exit(EXIT_SUCCESS);
}
```

## SEE ALSO

[**fgetpwent**(3)](/fgetpwent/3.md), [**getpw**(3)](/getpw/3.md), [**getpwent**(3)](/getpwent/3.md), [**getpwnam**(3)](/getpwnam/3.md), [**getpwuid**(3)](/getpwuid/3.md), [**putpwent**(3)](/putpwent/3.md), [**passwd**(5)](/passwd/5.md)