Add a new function dlversion() which returns the version number of

the dynamic linker in the same form as __FreeBSD_version.  This is
mainly intended for checking the dynamic linker version during a make
world.

1 files changed, 18 insertions, 1 deletions

diff --git a/lib/libc/gen/dlopen.3 b/lib/libc/gen/dlopen.3
index 9e848f9..e56e3ae 100644
--- a/lib/libc/gen/dlopen.3
+++ b/lib/libc/gen/dlopen.3
@@ -34,7 +34,7 @@
 .Os FreeBSD
 .Dt DLOPEN 3
 .Sh NAME
-.Nm dlopen, dlsym, dlerror, dlclose
+.Nm dlopen, dlsym, dlerror, dlclose, dlversion
 .Nd programmatic interface to the dynamic linker
 .Sh SYNOPSIS
 .Fd #include <dlfcn.h>
@@ -46,6 +46,8 @@
 .Fn dlerror "void"
 .Ft int
 .Fn dlclose "void *handle"
+.Ft int
+.Fn dlversion "void"
 .Sh DESCRIPTION
 These functions provide a simple programmatic interface to the services of the
 dynamic linker.
@@ -219,6 +221,19 @@ The object-intrinsic functions
 and
 .Fn _fini
 are called with no arguments, and are not expected to return values.
+.Pp
+.Fn dlversion
+returns the version number of the dynamic linker.  Interpreted
+as a decimal number, the version number has the form
+.Em rrrsss .
+.Em rrr
+corresponds to the base operating system release version, e.g., 400
+for release 4.0.0.
+.Em sss
+is a serial number that increases monotonically within each release
+version.  If the installed dynamic linker is too old to support
+.Fn dlversion ,
+0 is returned.
 .Sh NOTES
 ELF executables need to be linked
 using the
@@ -234,6 +249,8 @@ and
 return the null pointer in the event of errors.
 .Fn dlclose
 returns 0 on success, or -1 if an error occurred.
+.Fn dlversion
+returns 0 if the dynamic linker is too old to support it.
 Whenever an error has been detected, a message detailing it can be
 retrieved via a call to
 .Fn dlerror .