getpwuid_r()

Get information about the user with a given ID

Synopsis:

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

int getpwuid_r( uid_t uid,
                struct passwd* pwd, 
                char* buffer, 
                size_t bufsize, 
                struct passwd** result );

Description:

The getpwuid_r() function is a reentrant version of getpwuid(). It lets a process gain more knowledge about user with the given uid.

If _POSIX_THREAD_SAFE_FUNCTIONS is defined, the getpwuid_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 a matching uid.

Storage referenced by the structure is allocated from the memory provided with the buffer parameter, which is bufsize characters in size. The maximum size needed for this buffer can be determined by calling sysconf() with the argument _SC_GETPW_R_SIZE_MAX.

A NULL pointer is stored at the location pointed by result on error or if the requested entry isn't found.

Returns:

Zero for success, or an error number.

Errors:

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

The getpwuid_r() function uses the following functions, and as a result errno can be set to a valid error for any of these calls:

Classification:

POSIX 1003.1

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