ID Number: Q57948
5.00 5.10 6.00 6.00a 6.00ax 7.00 | 5.10 6.00 6.00a
MS-DOS | OS/2
Summary:
In Microsoft C versions 5.0, 5.1, 6.0, 6.0a, 6.0ax, and C/C++ version
7.0, if you enter the escape character (ASCII 1Bh) from the keyboard
(console) into a string that gets(), cgets(), or fgets() is reading, all
the string previously read in is erased. The string pointer is reset so
that characters following the escape character are read into the
beginning of the string. This is consistent with the action taken by the
operating system to parse the input line.
However, if the escape character is input from a file by redirection,
the entire string, including the escape character, will be read into
the string.
More Information:
Sample Code
-----------
/* Compile options needed: none
*/
#include <conio.h>
#include <stdio.h>
char buf[22];
char *result;
void main(void)
{
int i;
buf[0] = 20;
printf("Enter your text: \n");
result = gets(buf);
printf ( "Resulting String: %s\n", result );
for( i = 0; i < 20; i ++ )
{
printf("Buf[%2d] = %c (char)\n", i, buf[i]);
}
}
Enter the following string as a test:
abcdef<esc>ghijk
Note that the resulting string is output as:
ghijk
Now, using a text editor that will accept an escape character embedded
in a string, create a data file with the same string. If the above
program is run with input redirected from the data file, for example
program <test.dat
the resulting string is output as follows:
abcdef<esc>ghijk
This behavior occurs in the entire gets() family of routines,
including gets(), cgets(), and fgets(). If the input is coming from
the console, the run time will use the standard MS-DOS and OS/2
keyboard read routines. On the other hand, if the input is coming from
a file (through redirection), the operating system doesn't perform any
editing and the file is read in literally.
Additional reference words: 5.00 5.10 6.00 6.00a 6.00ax 7.00