getutline_r - Linux

Overview

The getutline_r command retrieves information from the user terminal database. It provides a convenient way to query and manipulate terminal information such as number of columns and rows, cursor position, and terminal type.

Syntax

int getutline_r(struct utmpx *utmpx, char *utline, size_t utlinesize)

Parameters:

• utmpx: A pointer to a utmpx structure to store the retrieved terminal information.
• utline: A buffer to store the terminal line name.
• utlinesize: The size of the utline buffer in bytes.

Options/Flags

None.

Examples

Get terminal information for the current user:

struct utmpx utmp;
char utline[64];

if (getutline_r(&utmp, utline, sizeof(utline)) == 0) {
    printf("Terminal: %s\n", utline);
} else {
    perror("getutline_r");
}

Get terminal information for a specific user:

struct utmpx utmp;
char utline[64];

if (getutline_r(&utmp, utline, sizeof(utline), "username") == 0) {
    printf("Terminal: %s\n", utline);
} else {
    printf("User not found: username\n");
}

Common Issues

• Invalid user name: If the specified user name does not exist, getutline_r will return -1 and set errno to ESRCH.
• Buffer size too small: If the utline buffer is not large enough to store the terminal line name, getutline_r will truncate the name.

Integration

getutline_r can be integrated with other terminal-related commands to manage terminal sessions. For example, it can be used to determine the terminal type for a given user, which can then be used to set appropriate terminal settings.

Related Commands

• getutent_r: Retrieves a terminal entry from the user terminal database.
• pututline_r: Updates a terminal entry in the user terminal database.
• utmpxname_r: Converts a terminal line name to a username.