Article: Q38026
Product(s): See article
Version(s): 5.10 | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | S_QUICKC | mspl13_c
Last Modified: 15-NOV-1988
Question:
Why is the minimum value of CHAR and INT off by one in the include
file limits.h?
Response:
This behavior occurs because there is no corresponding positive value
for the SIGNED CHAR's minimum value. For example, the range of a
SIGNED CHAR is -128 to 127. The range specified in limits.h is -127 to
127. The range of a signed int is -32768 to 32767, but limits.h
specifies the range as -32767 to 32767.
If you were to take the absolute value of -128 with the ABS() function,
you would expect to get +128. This is correct; however, you must
ensure that you store the result in a variable that has a storage
class that can represent the value.
For example, it does not make sense, and is not possible, to take the
absolute value of -128 and try and store it in a SIGNED CHAR. 127 is
the maximum positive value for a this storage class.
The return value from the ABS() function is undefined if you try
to store the result in a storage class that cannot represent the
value.