分类： LINUX
2008-12-05 10:03:32
写入/dev/tty可以在重定时依旧输出到当前屏幕。
实例：
# cat menu3.c
#include
#include
#include
char *menu[] = {
"a - add new record",
"d - delete record",
"q - quit",
NULL,
};
int getchoice(char *greet, char *choices[], FILE *in, FILE *out);
int main()
{
int choice = 0;
FILE *input;
FILE *output;
if (!isatty(fileno(stdout))) {
fprintf(stderr,"You are not a terminal, OK.\n");
}
input = fopen("/dev/tty", "r");
output = fopen("/dev/tty", "w");
if(!input || !output) {
fprintf(stderr,"Unable to open /dev/tty\n");
exit(1);
}
do {
choice = getchoice("Please select an action", menu, input, output);
printf("You have chosen: %c\n", choice);
} while (choice != 'q');
exit(0);
}
int getchoice(char *greet, char *choices[], FILE *in, FILE *out)
{
int chosen = 0;
int selected;
char **option;
do {
fprintf(out,"Choice: %s\n",greet);
option = choices;
while(*option) {
fprintf(out,"%s\n",*option);
option++;
}
do {
selected = fgetc(in);
} while (selected == '\n');
option = choices;
while(*option) {
if(selected == *option[0]) {
chosen = 1;
break;
}
option++;
}
if(!chosen) {
fprintf(out,"Incorrect choice, select again\n");
}
} while(!chosen);
return selected;
}
运行的结果：
# ./menu3 > file 2>&1
Choice: Please select an action
a - add new record
d - delete record
q - quit
a
Choice: Please select an action
a - add new record
d - delete record
q - quit
d
Choice: Please select an action
a - add new record
d - delete record
q - quit
q
# cat file
You are not a terminal, OK.
You have chosen: a
You have chosen: d
You have chosen: q
