enterchr.c File Reference

Enter a single character from keyboard. More...

#include <cm.h>
#include <fcntl.h>
#include <stdbool.h>
#include <string.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <unistd.h>

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Functions
int	main (int argc, char **argv)
	Capture the current terminal settings for later restoration.

Detailed Description

Enter a single character from keyboard.

Author

Bill Waller Copyright (c) 2025 MIT License billx.nosp@m.wall.nosp@m.er@gm.nosp@m.ail..nosp@m.com

Date

2026-02-09

Definition in file enterchr.c.

Function Documentation

main()

int main	(	int	argc,
		char **	argv )

Capture the current terminal settings for later restoration.

can be used in scripts to get a single character response from a user. For example: response=$(./enterchr "Enter Y or N: ") if [ "$response" = "Y" ]; then echo "You entered Yes" else echo "You entered No" fi This function saves the current terminal settings into a global variable so that they can be restored later. It should be called before modifying the terminal settings to ensure that the original settings can be restored when the program exits or is interrupted.

Definition at line 38 of file enterchr.c.

                                {
    char c = 'Y';
    char *msg;
    struct termios raw_tioctl;
    char errmsg[128];
 
    if (argc < 2)
        strcpy(errmsg, "Press any key");
    else
        strcpy(errmsg, argv[1]);
    capture_shell_tioctl();
    raw_tioctl = shell_tioctl;
    mk_raw_tioctl(&raw_tioctl);
    tcflush(0, TCOFLUSH);
    while (1) {
        msg = errmsg;
        while (*msg) {
            write(2, msg++, 1);
        }
        if (read(0, &c, 1) > 0) {
            write(1, &c, 1);
            break;
        }
    }
    restore_shell_tioctl();
    if (c == (char)0x1b)
        return (1);
    return (0);
}

References capture_shell_tioctl(), mk_raw_tioctl(), restore_shell_tioctl(), and shell_tioctl.

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