I am experiencing problems printing long int values under cygwin64 installed on
a Windows 10 machine.
Below is a test program followed by its output to demonstrate the problem. The
program was initially written to demonstrate the output from lrint(), and
developed further to demonstrate to myself how negative integers are tackled by
printf type specifiers (e.g. %li, %ld etc).
My understanding is that lrint() should return a long int. However I am unable
to get printf to print the correct number. Instead its output is treated as an
unsigned integer.
Any help or hints would be much appreciated.
Regards
Carl Fredrik
#include <stdio.h> /* printf */
#include <math.h> /* lrint */
int main ()
{
char text[64];
printf ( "int -2 = %i\n", -2 );
printf ( "int -1 = %i\n", -1 );
printf ( "int 0 = %i\n", 0 );
printf ( "int 1 = %i\n", 1 );
printf ( "long int -2 = %li\n", -2 );
printf ( "long int -1 = %li\n", -1 );
printf ( "type cast -1 = %li\n", (long int)-1 );
printf ( "type cast lrint(-1.0) = %li\n", (long int)lrint(-1.0) );
printf ( "lrint(-1.0) = %li\n", lrint(-1.0) );
printf ( "lrint(1.0) = %li\n", lrint(1.0) );
printf ( "long int 0 = %li\n", 0 );
printf ( "long int 1 = %li\n", 1 );
sprintf( text,"long int -1 = %li", -1 );
printf ( "Via sprintf: %s\n", text);
printf ( "size of long int: %i\n", sizeof(long int));
printf ( "size of int: %i\n", sizeof(int));
return 0;
}
compiled by:
gcc lrint_test.c -o lrint_test.exe
Output:
int -2 = -2
int -1 = -1
int 0 = 0
int 1 = 1
long int -2 = 4294967294
long int -1 = 4294967295
type cast -1 = -1
type cast lrint(-1.0) = 4294967295
lrint(-1.0) = 4294967295
lrint(1.0) = 1
long int 0 = 0
long int 1 = 1
Via sprintf: long int -1 = 4294967295
size of long int: 8
size of int: 4
gcc version:
gcc (GCC) 5.4.0
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