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isatty |
Portability: | POSIX.1 conforming, UNIX compatible |
SYNOPSIS | |
DESCRIPTION | |
RETURN VALUE | |
EXAMPLE | |
RELATED FUNCTIONS | |
SEE ALSO |
SYNOPSIS |
#include <lcio.h> int isatty(int fn);
The syntax for the POSIX implementation is
#include <sys/types.h> #include <unistd.h> int isatty(int fn);
DESCRIPTION |
isatty
tests whether the file associated with file number
fn
is an interactive terminal.
isatty
returns a non-zero value if the file number represents a TSO terminal, a CMS
terminal, or an USS terminal.
isatty
returns
0 for the DDname SYSTERM when called under OS/390 batch.
RETURN VALUE |
EXAMPLE |
#include <lcio.h> #include <stdio.h> double point[40]; main() { FILE *f; int index = 0; double sum = 0.0; double avg ; int nopoints; int fn =0; /* If stdin is the terminal, (fileno(stdin) is always 0). */ if (isatty(fn)) /* Tell user to enter data points - max. = 39. */ puts("Enter data points (-1 to indicate end of list)."); for(;;){ /* Read number; check for end of file. */ if (scanf("%le", &point[index]) <= 0) break; if (point[index] == -1) break; sum += point[index]; ++index; } nopoints = index; avg = sum / nopoints; printf("%d points read.\n", nopoints); printf("%f = average.\n", avg); }
RELATED FUNCTIONS |
SEE ALSO |
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