HP-UX Reference (11i v2 04/09) - 3 Library Functions A-M (vol 6)

crt0_ia(3) crt0_ia(3)

(For Itanium(R)-based Systems)

NAME

crt0_ia: crt0.o - execution startup routines

DESCRIPTION

The C, aC++, and FORTRAN compilers link in the object ﬁle

crt0.o for statically-bound programs to

provide startup capabilities and environments for program execution. It contains startup code that must

be linked using

ld to every statically-bound program. In a dynamically linked program (the default

method), the crt0.o object ﬁle is not used, and all actions normally associated with it are instead done

by the dynamic loader dld.so(5).

crt0.o processes initializers and terminators . Initializers are routines that are called before the pro-

gram entry point and terminators are routines that are called when the program terminates via the

exit

routine. Initializers are invoked in reverse order of the link line so that dependent libraries are initial-

ized before the libraries that depend on them. Terminators, on the other hand, are invoked in the for-

ward order.

crt0.o does not deﬁne any variables. It, however, sets the following global variables:

_ _argc A variable of type long containing the number of arguments.

_ _argv An array of character pointers to the arguments themselves.

_environ, __envp

An array of character pointers to the environment in which the program will

run. This array is terminated by a null pointer.

_SYSTEM_ID A variable of type long containing the system id value for an executable pro-

gram.

__tls_size A variable of type long containing the requested thread local storage size.

This variable is initialized with data from the kernel.

__load_info A variable of type void * containing load information passed from the kernel.

AUTHOR

The features described in this entry originated from AT&T UNIX System III.

FILES

crt0.h