fopen -- Open a File


SYNOPSIS
#include <stdio.h>
FILE *fopen(const char *name, const char *mode);
DESCRIPTION
The fopen
function opens a file and returns a pointer to the
associated FILE
object. The name
argument is the
external name (sometimes called a pathname) of the file to be
opened. Its form is system dependent. The mode
argument is a
string defining how the file will be used. For more information about
open mode values, see Open modes .
RETURN VALUE
The fopen
function returns a pointer to a FILE
object associated
with the named file. If the file cannot be opened, a NULL
value is
returned.
IMPLEMENTATION
At most, 256 files can be open at one time, including the three
standard files.
EXAMPLE
This example opens for a
the second time to add an additional line
to the file:
#include <stdio.h>
main()
{
FILE* test;
int c;
float a;
test = fopen("tso:TEST", "w");
puts("Enter maximum speed limit in miles:");
scanf("%d", &c);
fprintf(test, "Maximum speed limit is %d miles/hour.n", c);
fclose(test);
a = 1.619 * c;
test = fopen("tso:TEST", "a");
fprintf(test, "n In km/h, the maximum speed limit is %fn", a);
fclose(test);
}
RELATED FUNCTIONS
afopen
, freopen
, open
SEE ALSO