2: Dynamic Load

Load C shared objects

Syntax: x 2: y, 2:[x;y]

Where

  • x is a file symbol
  • y is a 2-item list: the name of a C function (symbol) and its rank (int)

returns a function that calls it.

Suppose we have a C function in cpu.so with the prototype

K q_read_cycles_of_this_cpu(K x);

assign it to read_cycles:

read_cycles:`cpu 2:(`q_read_cycles_of_this_cpu;1)

If the shared library, as passed, does not exist, kdb+ will try to load it from $QHOME/os, where os is the operating system and architecture acronym, e.g. l64, w64, etc. If using a relative path which does not resolve to reside under $QHOME/os, ensure that LD_LIBRARY_PATH contains the required absolute search path for that library. On Windows, use PATH instead of LD_LIBRARY_PATH.

Basics: File system
Interfaces: Using C/C++ functions