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authorRuslan Ermilov <ru@FreeBSD.org>2002-12-18 10:13:54 +0000
committerRuslan Ermilov <ru@FreeBSD.org>2002-12-18 10:13:54 +0000
commit95f4226b2755f1600e3bf4e32e8aa0db0886c280 (patch)
treed7fc87dbba410fea9fb526ffb94f2409d3c5f8cc /lib/libc/gen/dlopen.3
parentb92cc9b8783fe78fa7d6f4ad6b005d29e28cd99c (diff)
downloadsrc-95f4226b2755f1600e3bf4e32e8aa0db0886c280.tar.gz
src-95f4226b2755f1600e3bf4e32e8aa0db0886c280.zip
Notes
Diffstat (limited to 'lib/libc/gen/dlopen.3')
-rw-r--r--lib/libc/gen/dlopen.320
1 files changed, 19 insertions, 1 deletions
diff --git a/lib/libc/gen/dlopen.3 b/lib/libc/gen/dlopen.3
index c1c09e4436da..ba37c6f2c9a6 100644
--- a/lib/libc/gen/dlopen.3
+++ b/lib/libc/gen/dlopen.3
@@ -60,7 +60,9 @@ program's address space, to obtain the address bindings of symbols
defined by such
objects, and to remove such objects when their use is no longer required.
.Pp
+The
.Fn dlopen
+function
provides access to the shared object in
.Fa path ,
returning a descriptor that can be used for later
@@ -141,7 +143,9 @@ fails, it returns a null pointer, and sets an error condition which may
be interrogated with
.Fn dlerror .
.Pp
+The
.Fn dlsym
+function
returns the address binding of the symbol described in the null-terminated
character string
.Fa symbol ,
@@ -225,17 +229,23 @@ interface, below, should be used, since
.Fn getpid
is a function and not a data object.)
.Pp
+The
.Fn dlsym
+function
returns a null pointer if the symbol cannot be found, and sets an error
condition which may be queried with
.Fn dlerror .
.Pp
+The
.Fn dlfunc
+function
implements all of the behavior of
.Fn dlsym ,
but has a return type which can be cast to a function pointer without
triggering compiler diagnostics.
-.Fn ( dlsym
+(The
+.Fn dlsym
+function
returns a data pointer; in the C standard, conversions between
data and function pointer types are undefined.
Some compilers and
@@ -246,7 +256,9 @@ The precise return type of
is unspecified; applications must cast it to an appropriate function pointer
type.
.Pp
+The
.Fn dlerror
+function
returns a null-terminated character string describing the last error that
occurred during a call to
.Fn dlopen ,
@@ -266,7 +278,9 @@ to
where the second call follows the first immediately, the second call
will always return a null pointer.
.Pp
+The
.Fn dlclose
+function
deletes a reference to the shared object referenced by
.Fa handle .
If the reference count drops to 0, the object is removed from the
@@ -306,12 +320,16 @@ still the case when using the (obsolete)
.Fl aout
option to the C language compiler.
.Sh ERRORS
+The
.Fn dlopen ,
.Fn dlsym ,
and
.Fn dlfunc
+functions
return a null pointer in the event of errors.
+The
.Fn dlclose
+function
returns 0 on success, or -1 if an error occurred.
Whenever an error has been detected, a message detailing it can be
retrieved via a call to