{"id":7419,"date":"2026-02-28T00:01:42","date_gmt":"2026-02-28T08:01:42","guid":{"rendered":"https:\/\/c-for-dummies.com\/blog\/?p=7419"},"modified":"2026-03-07T07:46:36","modified_gmt":"2026-03-07T15:46:36","slug":"accessing-the-mouse-in-a-terminal-window","status":"publish","type":"post","link":"https:\/\/c-for-dummies.com\/blog\/?p=7419","title":{"rendered":"Accessing the Mouse in a Terminal Window"},"content":{"rendered":"

\"\"
\nThe point of reading and capturing mouse data is to do something at the mouse’s location. Specifically, the goal is to have the terminal somehow react to a mouse click. Yes, even though C is stream oriented and rarely involves graphics or the mouse, this feat is made possible thanks to ANSI commands.
\n
\nLast week’s Lesson<\/a> covered how to capture and store mouse input. For today’s lesson, this data is used along with ANSI cursor manipulation sequences to report mouse movement and to set a character at the location in the terminal window where the mouse is clicked.<\/p>\n

Seriously, I didn’t think such a trick would be possible in C without benefit of a library such as Ncurses. But, yes, providing that you’ve followed along with the last few posts here, this feat is entirely possible.<\/p>\n

The following code updates what was presented in last week’s lesson. I’ve added two ANSI macros: clear()<\/em><\/a> and moveto()<\/em> (based on another macro, locate()<\/em>, presented in an earlier Lesson<\/a>).<\/p>\n

Most of new code appear in the main()<\/em> function, where the while<\/em> loop contains an if-else<\/em> decision to output information based on whether the mouse is moving or has been clicked. The screen is updated to reflect the click and button number.<\/p>\n

2026_02_28-Lesson.c<\/a><\/h3>\n
\r\n#include <stdio.h>\r\n#include <stdlib.h>\r\n#include <ctype.h>\r\n#include <termios.h>\r\n#include <unistd.h>\r\n\r\n#define clear() printf(\"\\e[H\\e[2J\")\r\n#define moveto(a,b) printf(\"\\e[%d;%dH\",b,a)\r\n#define mouse_enable() printf(\"\\e[?1000h\")\r\n#define mouse_motion() printf(\"\\e[?1003h\")\r\n#define mouse_extended() printf(\"\\e[?1006h\")\r\n#define mouse_disable() printf(\"\\e[?1000l\")\r\n\r\nstruct mouse_data {\r\n    int button;\r\n    int column;\r\n    int row;\r\n};\r\n\r\n\/* read an integer from a string\r\n   Exercise 2026_02 *\/<\/span>\r\nchar *extract(char *s)\r\n{\r\n    static char *sp;\r\n\r\n    \/* check for recall *\/<\/span>\r\n    if( s != NULL )\r\n        sp = s;\r\n    else\r\n        while( isdigit(*sp) )\r\n            sp++;\r\n\r\n    \/* find the next digit *\/<\/span>\r\n    while( *sp != '\\0' )\r\n    {\r\n        if( isdigit(*sp) )\r\n        {\r\n            return(sp);\r\n        }\r\n        sp++;\r\n    }\r\n\r\n    return(NULL);\r\n}\r\n\r\n\/* obtain values from mouse data *\/<\/span>\r\nvoid read_mouse(char *b, struct mouse_data *m)\r\n{\r\n    m->button = atoi(extract(b));\r\n    m->column = atoi(extract(NULL));\r\n    m->row = atoi(extract(NULL));\r\n}\r\n\r\nint main()\r\n{\r\n    struct termios original,noecho;\r\n    struct mouse_data mickey;\r\n    char buffer[13];\r\n    int key;\r\n\r\n    \/* obtain terminal configuration *\/<\/span>\r\n    tcgetattr(fileno(stdin),&original);\r\n    noecho = original;        \/* duplicate *\/<\/span>\r\n        \/* enable raw input *\/<\/span>\r\n    noecho.c_lflag = noecho.c_lflag ^ ICANON;\r\n        \/* disable full duplex *\/<\/span>\r\n    noecho.c_lflag = noecho.c_lflag ^ ECHO;\r\n        \/* update terminal definition *\/<\/span>\r\n    tcsetattr(fileno(stdin), TCSANOW, &noecho);\r\n\r\n    \/* enable mouse reporting *\/<\/span>\r\n    mouse_enable();\r\n    mouse_motion();\r\n    mouse_extended();\r\n    \/* remove line buffering *\/<\/span>\r\n    setvbuf(stdin,NULL,_IONBF,0);\r\n\r\n    \/* read stdin *\/<\/span>\r\n    clear();\r\n    puts(\"Play with the mouse; press Enter  to end\");\r\n    while( (key=getchar()) != '\\n' )\r\n    {\r\n        read(fileno(stdin),buffer,12);\r\n        buffer[12] = '\\0';        \/* make it a string *\/<\/span>\r\n        read_mouse(buffer,&mickey);\r\n        if( mickey.button != 35 )\r\n        {\r\n            clear();\r\n            moveto(mickey.column,mickey.row);\r\n            printf(\"%d\",mickey.button);\r\n            moveto(1,1);\r\n            printf(\"Button %d clicked at column %d row %d\\n\",\r\n                    mickey.button,\r\n                    mickey.column,\r\n                    mickey.row\r\n                  );\r\n        }\r\n        else\r\n        {\r\n            clear();\r\n            printf(\"Mouse moving to column %d row %d\\n\",\r\n                    mickey.column,\r\n                    mickey.row\r\n                  );\r\n        }\r\n    }\r\n\r\n    \/* clean-up *\/<\/span>\r\n    mouse_disable();    \/* disable mouse reporting *\/<\/span>\r\n    tcsetattr(fileno(stdin), TCSANOW, &original);\r\n    return 0;\r\n}<\/pre>\n
The main()<\/em> function’s while<\/em> loop monitors standard input. The input is captured and sent to the read_mouse()<\/em> function. After extraction and storage in the mouse_data<\/em> mickey<\/code> structure, an if<\/em> decision determines whether the “button” value isn’t 35, meaning that a mouse button has been clicked. When true, the button number is output at the click’s position. The else<\/em> part of the loop reports the mouse’s current location.<\/p>\n
The loop repeats until the Enter key is pressed.<\/p>\n
Figure 1 shows a sample run.<\/p>\n
\"Terminal
Figure 1. The program tracks mouse movements and clicks.<\/p><\/div>\n
This code goofs up if the terminal features a scrollback buffer and you drag the mouse on the screen or shift-click. Remember, these are ANSI codes and not a full-screen terminal API like Ncurses. (If the terminal window screws up, use the reset<\/em> command to set things straight.)<\/p>\n
For next week’s Lesson<\/a>, I wrap up the mouse manipulation series by working with text output at the click points.<\/p>\n","protected":false},"excerpt":{"rendered":"
Time to put the mouse to work! Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-7419","post","type-post","status-publish","format-standard","hentry","category-main"],"_links":{"self":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7419","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7419"}],"version-history":[{"count":5,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7419\/revisions"}],"predecessor-version":[{"id":7463,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7419\/revisions\/7463"}],"wp:attachment":[{"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7419"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7419"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/c-for-dummies.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7419"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}