APPENDIX C
992
Implementation Limits
limits, applications producing PDF files are strongly advised to remain within
them. Note, however, that memory limits are often exceeded before architectural
limits (such as the limit on the number of indirect objects) are reached.
TABLE C.1 Architectural limits
QUANTITY
LIMIT
DESCRIPTION
integer
2,147,483,647
-2,147,483,648
Largest integer value; equal to 2
31
−
1.
Smallest integer value; equal to
−2
31
.
Largest and smallest real values (approximate).
Nonzero real values closest to 0 (approximate). Values closer
than these are automatically converted to 0.
real
±
3.403
×
10
38
±
1.175
×
10
5
38
Number of significant decimal digits of precision in fractional
part (approximate).
Note:
To represent real numbers, Acrobat 6 uses IEEE single-precision floating-point
numbers, as described in the IEEE Standard for Binary Floating-Point Arithmetic (see
the Bibliography). Previous versions used 32-bit fixed-point numbers (16 bits on either
side of the radix point), which have greater precision but a much smaller range than
IEEE floating-point numbers. (Acrobat 6 still converts floating-point numbers to fixed
point for some components, such as screen display and fonts.)
string (in content
stream)
32,767
Maximum length of a string, in bytes.
Note:
This restriction applies only to strings in content streams.
There is no effective restriction on other strings in PDF files.
127
8,388,607
28
Maximum length of a name, in bytes.
Maximum number of indirect objects in a PDF file.
Maximum depth of graphics state nesting by
q
and
Q
operators.
(This is not a limit of Acrobat as such, but arises from the fact
that
q
and
Q
are implemented by the PostScript
gsave
and
gre-
store
operators when generating PostScript output; see imple-
Maximum number of colorants or tint components in a
DeviceN
color space.
Maximum value of a CID (character identifier).
name
indirect object
q
/
Q
nesting
DeviceN
components
32
65,535
CID