HP-UX Reference (11i v1 00/12) - 3 Library Functions N-Z (vol 7)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD

/build/1111/BRICK/man3/nan.3m

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shl_load(3X) shl_load(3X)

struct shl_symbol {

char *name,

short type,

void *value,

shl_t handle,

};

The type ﬁeld in the return structure can have the values TYPE_PROCEDURE,or

TYPE_DATA. On PA32, you can also have the values TYPE_STORAGE or

TYPE_TSTORAGE . These are a subset of TYPE_DATA. The value and handle ﬁelds

are only valid if export symbols are requested and the NO_VALUES ﬂag is not

speciﬁed. The value ﬁeld contains the address of the symbol, while the handle ﬁeld is

the handle of the library that deﬁned the symbol, or NULL for symbols deﬁned via the

shl_definesym() routine and is useful in conjunction with the

GLOBAL_VALUES ﬂag.

If successful, shl_getsymbols() returns the number of symbols found; other-

wise it returns −1.

shl_unload() Can be used to detach a shared library from the process. The handle argument

should be the handle returned from a previous call to

shl_load(). On PA64, you

can also get the handle from a call to

dlopen(). shl_unload() returns 0 if

successful; otherwise −1 is returned. Any initializers registered with the library are

called before detachment. All explicitly loaded libraries are detached automatically on

process termination.

The same shared library can be opened multiple times. On PA32, shl_unload

unloads the shared library regardless of whether there are other references to it

through other load invocations or through implicit references from other shared

libraries. No reference count is kept. On PA64, a reference counter is kept for each

loaded shared library, like the behavior of dlopen(3C) and dlclose(3C).

shl_unload does not remove the shared library from the address space until all

references to that shared library have been removed.

shl_get() Returns information about currently loaded libraries, including those loaded implicitly

at startup time. The index argument is the ordinal position of the shared library in

the shared library search list for the process. A subsequent call to shl_unload()

or dlclose() decrements the index values of all libraries having an index greater

than the unloaded library. The index value −1 refers to the dynamic loader. The desc

argument is used to return a pointer to a statically allocated buffer containing a

descriptor for the shared library. The format of the descriptor is implementation

dependent; to examine its format, look at the contents of ﬁle

/usr/include/dl.h

. Information common to all implementations includes the

library handle, pathname, and the range of addresses the library occupies. The buffer

for the descriptor used by

shl_get() is static; the contents should be copied else-

where before a subsequent call to the routine. The routine returns 0 normally, or −1if

an invalid index is given.

shl_gethandle()

Returns information about the library speciﬁed by the handle argument. The special

handle PROG_HANDLE can be used to refer to the program itself. The descriptor

returned is the same as the one returned by the shl_get() routine. The buffer for

the descriptor used by shl_gethandle()

is static; the contents should be copied

elsewhere before a subsequent call to the routine. The routine returns 0 normally, or

−1 on error.

shl_get_r() This is a reentrant version of shl_get(). The desc argument must point to a buffer

of enough user-deﬁned storage to be ﬁlled with the library descriptor described in

/usr/include/dl.h. Its semantics are otherwise identical to shl_get().

shl_gethandle_r()

This is a reentrant version of shl_gethandle(). The desc argument must point

to a buffer of enough user-deﬁned storage to be ﬁlled with the library descriptor

described in /usr/include/dl.h

. Its semantics are otherwise identical to

shl_gethandle().

Section 3−−854 − 4 − HP-UX Release 11i: December 2000

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