trapchk

Purpose

Tests the value of the trap flag.

Format

y = trapchk(m)
Parameters

m (scalar) – mask value

Returns

y (scalar) – the result of the bitwise logical AND of the trap flag and the mask value.

Remarks

To check the various bits in the trap flag, add the decimal values for the bits you wish to check according to the chart below and pass the sum in as the argument to the trapchk() function:

bit

decimal value

0

1

1

2

2

4

3

8

4

16

5

32

6

64

7

128

8

256

9

512

10

1024

11

2048

12

4096

13

8192

14

16384

15

32768

If you want to test if either bit 0 or bit 8 is set, then pass an argument of 1+256 or 257 to trapchk(). The following table demonstrates values that will be returned for:

y = trapchk(257);

0

1

value of bit 0 in trap flag

0

0

1

1

256

257

value of bit 8 in trap flag

GAUSS functions that test the trap flag currently test only bits 0 and 1.

See also

Functions scalerr(), trap, error()