Datasheet

The C and C++ Libraries
ARM DUI 0067D Copyright © 1999-2001 ARM Limited. All rights reserved. 4-5
The following points describe how static data is used by the libraries:
• Floating-point arithmetic libraries do not use static data and are always reentrant.
• All statically-initialized data in the C libraries is read-only.
• All writable static data is uninitialized.
• Most C library functions use no writable static data and are reentrant whether built
with base build options (
-apcs /norwpi ) or reentrant ( -apcs /rwpi ) build options.
• A few functions have static data in their definitions (see Table 4-1). You must not
use these, or other similar functions, in a reentrant application unless you build it
-apcs /rwpi .
Caution
The number of functions that use static data in their definitions might change in future
versions of ADS.
Table 4-1 Library functions that use static data
Function Description
strtok() Contains implicit static data
gamma() and lgamma() These functions, in math.h , use a global variable called
signgam
rand()
and srand() Require a random seed
stdin , stdout , and stderr These are static data
atexit() Stores exit handlers in static data
setlocale() , asctime() ,
localtime() , localeconv() , and
tmpnam()
Return pointers to static data
__user_libspace() This function is used by many other routines
_sys_clock() The default implementation has a static variable that
stores the time-at-start-of-program
fenv.h functions These are used to install FP exception traps
signal.h functions These are used to install signal handlers