getpass Subroutine
Purpose
Reads a password.
Library
Standard C Library (libc.a)
Syntax
#include <stdlib.h>char *getpass ( Prompt)
char *Prompt;
char *Prompt;
Description
Attention: The
characters are returned in a static data area. Subsequent calls to
this subroutine overwrite the static data area.
The getpass subroutine does the following:
- Opens the controlling terminal of the current process.
- Writes the characters specified by the Prompt parameter to that device.
- Reads from that device the number of characters up to the value of the PASS_MAX constant until a new-line or end-of-file (EOF) character is detected.
- Restores the terminal state and closes the controlling terminal.
During the read operation, character echoing is disabled.
The getpass subroutine is not safe in a multithreaded environment. To use the getpass subroutine in a threaded application, the application must keep the integrity of each thread.
Parameters
| Item | Description |
|---|---|
| Prompt | Specifies a prompt to display on the terminal. |
Return Values
If this subroutine is successful, it returns a pointer to the string. If an error occurs, the subroutine returns a null pointer and sets the errno global variable to indicate the error.
Error Codes
If the getpass subroutine is unsuccessful, it returns one or more of the following error codes:
| Item | Description |
|---|---|
| EINTR | Indicates that an interrupt occurred while the getpass subroutine was reading the terminal device. If a SIGINT or SIGQUIT signal is received, the getpass subroutine terminates input and sends the signal to the calling process. |
| ENXIO | Indicates that the process does not have a controlling terminal. |
Note: Any subroutines called by the getpass subroutine may set other error codes.