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DosQueryModuleHandle returns the handle of a dynamic link module that was previously loaded.


DosQueryModuleHandle(pszModname, phmod)


pszModname (PSZ) - input 
The address of an ASCIIZ name string containing the dynamic link module name. The file-name extension used for dynamic link libraries is .DLL.
phmod (PHMODULE) - output 
The address of a doubleword in which the handle for the dynamic link module is returned.

Return Code

ulrc (APIRET) - returns
DosQueryModuleHandle returns one of the following values:
  • 0 NO_ERROR


The module name must match the name of the module already loaded. Otherwise, an error code is returned. This is a way of testing whether a dynamic link module is already loaded.

Example Code

This example attempts to obtain the handle of a dynamic link module. This allows the caller to test whether a given dynamic link module is currently loaded.

#define INCL_DOSMODULEMGR   /* Module Manager values */
#define INCL_DOSERRORS      /* DOS Error values */
#include <os2.h>
#include <stdio.h>

int main(VOID) {
   PSZ     ModuleName    = "C:\\OS2\\DLL\\DISPLAY.DLL";  /* Module name   */
   HMODULE ModuleHandle  = NULLHANDLE;                   /* Module handle */
   APIRET  rc            = NO_ERROR;                     /* Return code   */

   rc = DosQueryModuleHandle(ModuleName,      /* Module to look for       */
                             &ModuleHandle);  /* Handle (returned)        */
   if (rc != NO_ERROR) {
      printf("DosQueryModuleHandle error: return code = %u\n", rc);
      return 1;
   } else {
      printf ("Module handle = %u\n", ModuleHandle);

   rc = DosQueryModuleName (ModuleHandle,   /* Module handle to query     */
                            256L,           /* Maximum length of result   */
                            ModuleName);    /* Module name returned       */

   if (rc != NO_ERROR) {
      printf("DosQueryModuleName error: return code = %u\n", rc);
      return 1;
   } else {
      printf ("Module name = %s\n", ModuleName);
   return NO_ERROR;

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