dllqueryvar() — Obtain a pointer to a dynamic link library variable

Standards

Standards / Extensions C or C++ Dependencies
C Library both  

Format

#include <dll.h>

void* dllqueryvar(dllhandle *dllHandle, const char *varName);

General description

Obtains a pointer to a dynamic link library (DLL) variable (varName). It uses the dllHandle returned from a previous successful call to dllload() for input. varName represents the name of an exported variable from the DLL. It must be a character string terminated with the NULL character.

This function is not available under SPC, MTF and CSP environments.

Returned value

If successful, dllqueryvar() returns a pointer to a variable in the storage of the DLL.

If unsuccessful, dllqueryvar() returns NULL and sets errno.

Usage notes

  1. More detailed diagnostic information is available through the _EDC_DLL_DIAG environment variable, and the Language Environment® DLL Failure control block (CEEDLLF) chain.

Example

CELEBDL3 
/* CELEBDL3

   The following example shows how to use dllqueryvar() to obtain a
   pointer to a variable, var1, that is in DLL load module stream.

 */
#include <stdio.h>
#include <dll.h>

int main() {
    dllhandle *handle;
    char *name="stream";
    int (*fptr1)(int);
    int *ptr_var1;
    int rc=0;

    handle = dllload(name);
    if (handle == NULL) {
       perror("failed on dllload of stream DLL");
       exit(-1);
    }

    fptr1 = (int (*)(int)) dllqueryfn(handle,"f1");
    /* retrieving f1 function */
    if (fptr1 == NULL) {
       perror("failed on retrieving f1 function");
       exit(-2);
    }

    ptr_var1 = dllqueryvar(handle,"var1");
    if (ptr_var1 == NULL) {
       perror("failed on retrieving var1 variable");
       exit(-3);
    }
}

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