The following is an example of how to call all the latch manager services in C language:

/*********************************************************************/
/* C Example                                                         */
/*********************************************************************/
#pragma linkage(setsup, OS)
#pragma linkage(setprob, OS)
#include <ISGLMC.H>                 /* Include C language IDF        */

main()
{
  const int numberOfLatches = 16;   /* in this example we create 16
                                       latches                       */
  ISGLM_LSNM_type latchSetName
                  = "EXAMPLE.ONE_LATCH_SET_NAME                      ";
                                    /* set up 48-byte latch set name */
  ISGLM_LSTK_type latchSetToken;    /* latch set token - output from
                                       create and input to obtain,
                                       release, and purge            */
  int returnCode = 0;               /* return code from services     */

  const int latchNumber = 6;        /* in this example we obtain latch
                                       six                           */
  ISGLM_LRID_type requestorID = "123";/* requestor ID - output from
                                       obtain and input to purge     */
  int ECB = 0;                      /* ECB used for latch obtain
                                       service                       */
  ISGLM_EADDR_type ECBaddress = &ECB;/* pointer to ECB               */
  ISGLM_LTK_type latchToken;        /* latch token - output from
                                       obtain and input to release   */
  union {
          double alignment;         /* force double word alignment   */
          ISGLM_WA_type area;       /* set up work area              */
        } work;


  setsup();                         /* set supervisor state PSW      */

/*********************************************************************/
/* create a latch set with 16 latches                                */
/*********************************************************************/

  isglcrt(numberOfLatches
         ,latchSetName
         ,ISGLCRT_PRIVATE
         ,&latchSetToken;
         ,&returnCode);

/*********************************************************************/
/* obtain latch                                                      */
/*********************************************************************/

  isglobt(latchSetToken
         ,latchNumber
         ,requestorID
         ,ISGLOBT_SYNC              /* suspend until granted         */
         ,ISGLOBT_EXCLUSIVE         /* access option (exclusive)     */
         ,&ECBaddress               /* required, but not used        */
         ,&latchToken               /* identifies request            */
         ,&work.area
         ,&returnCode);

/*********************************************************************/
/* release latch                                                     */
/*********************************************************************/

  isglrel(latchSetToken
         ,latchToken
         ,ISGLREL_UNCOND            /* ABEND if latch not owned      */
         ,&workarea
         ,&returnCode);

/*********************************************************************/
/* purge requestor from latch set                                    */
/*********************************************************************/

  isglprg(latchSetToken
         ,requestorID
         ,&returnCode);

  setprob();                        /* set problem state PSW         */
}
**********************************************************************
* SETSUP subroutine
**********************************************************************
SETSUP   CSECT
SETSUP   AMODE 31
SETSUP   RMODE ANY
         SAVE  (14,12)             save regs
         SAC   0                   ensure primary mode
         LR    12,15               establish addressability
         USING SETSUP,12
         MODESET MODE=SUP          set supervisor state
         RETURN (14,12),RC=0       restore caller's regs and return
         END SETSUP
**********************************************************************
* SETPROB subroutine
**********************************************************************
SETPROB  CSECT
SETPROB  AMODE 31
SETPROB  RMODE ANY
         SAVE  (14,12)             save regs
         LR    12,15               establish addressability
         USING SETPROB,12
         MODESET MODE=PROB         set problem state
         RETURN (14,12),RC=0       restore caller's regs and return
         END SETPROB