getpwnam_r()

Updated: April 19, 2023

Get information about the user with a given name

Synopsis:

#include <sys/types.h>
#include <pwd.h>

int getpwnam_r( const char *name, 
                struct passwd *pwd, 
                char *buffer, 
                size_t bufsize, 
                struct passwd **result );

Arguments:

name
The name of the user whose entry you want to find.
pwd
A pointer to a passwd structure where the function can store the entry.
buffer
A block of memory that the function can use to allocate storage referenced by the passwd structure. You can determine the maximum size needed for this buffer by calling sysconf() with an argument of _SC_GETPW_R_SIZE_MAX.
bufsize
The size of the block that buffer points to, in characters.
result
The address of a pointer to a passwd structure. If getpwnam_r() finds the entry, it stores a pointer to pwd in the location indicated by result; otherwise the function stores a NULL pointer there.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The getpwnam_r() function is a reentrant version of getpwnam(). It gets information about the user with the given name.

The getpwnam_r() function updates the passwd structure pointed to by pwd and stores a pointer to that structure at the location pointed by result. The structure contains an entry from the user database with the given name.

The function stores a NULL pointer at the location pointed by result on error or if it can't find the requested entry.

Returns:

Zero for success, or an error number:

ERANGE
Insufficient storage was supplied via buffer and bufsize to contain the resulting passwd structure.

The getpwnam_r() function can also return any error code that the following functions indicate:

Classification:

POSIX 1003.1

Safety:  
Cancellation point Yes
Interrupt handler No
Signal handler No
Thread Yes