X Window System interface in the MVS environment: Reentrant modules

The following lines describe the additions that you must make to the compilation step of your cataloged procedure to compile a reentrant module. Cataloged procedures are included in the samples supplied by IBM® for your MVS™ system.

Note: Compile all C source using the def(IBMCPP) preprocessor symbol. See X Window System interface in the MVS environment: Compiling and linking for information about compiling and linking your program in MVS.

Add the following statement as the first //SYSLIB DD statement:
```
       //SYSLIB  DD  DSN=SEZACMAC,DISP=SHR
```

Add the following //USERLIB DD statement:

       //USERLIB DD  DSN=user_id.MYPROG.H,DISP=SHR

The following lines describe the additions that you must make to the prelink-edit and link-edit steps of your cataloged procedure to create a reentrant module.

To create reentrant modules that use only the X11 library functions, do the following:
- Add the following statement as the first //SYSLIB DD statement in the prelink-edit step:
```
       //         DD  DSN=SEZARNT1,DISP=SHR
```
- Add the following statement as the first //SYSLIB DD statement in the link-edit step:
```
       //         DD  DSN=SEZACMTX,DISP=SHR
```
To create reentrant modules that use only the Athena Toolkit functions, including Athena widget sets, do the following:
- Add the following statements as the first //SYSLIB DD statements in the prelink-edit step:
```
       //         DD  DSN=SEZARNT2,DISP=SHR
       //         DD  DSN=SEZARNT1,DISP=SHR
```
- Add the following statement as the first //SYSLIB DD statement in the link-edit step:
```
       //         DD  DSN=SEZACMTX,DISP=SHR
```
To create reentrant modules that use only the Motif Toolkit functions, do the following:
- Add the following statements as the first //SYSLIB DD statements in the prelink-edit step:
```
       //         DD  DSN=SEZARNT3,DISP=SHR
       //         DD  DSN=SEZARNT1,DISP=SHR
```
- Add the following statement as the first //SYSLIB DD statement in the link-edit step:
```
       //         DD  DSN=SEZACMTX,DISP=SHR
```

Following is a sample cataloged procedure for an X11 library function.

//*-------------------------------------------------------------
//* PRELINK-EDIT STEP:
//*-------------------------------------------------------------
//PRELNK  EXEC PGM=EDCPRLK,REGION=4096K,COND=(4,LT),
//          PARM='MAP,NONCAL'
//STEPLIB   DD DSN=C370.LL.V2R1M0.SEDCLINK,DISP=SHR
//          DD DSN=C370.LL.V2R1M0.COMMON.SIBMLINK,DISP=SHR
//          DD DSN=C370.LL.V2R1M0.SEDCCOMP,DISP=SHR
//SYSLIB    DD DSN=B37.SEZARNT1,DISP=SHR
//OBJLIB    DD DSN=&OBJLIB;,DISP=SHR;
//SYSMOD    DD UNIT=VIO,SPACE=(TRK,(50,10)),DISP=(MOD,PASS),
//             DCB=(RECFM=FB,LRECL=80,BLKSIZE=3120)
//SYSMSGS   DD DSN=C370.V2R1M0.SEDCMSGS(EDCMSGE),DISP=SHR
//SYSPRINT  DD SYSOUT=&SYSOUT;
//SYSOUT    DD SYSOUT=&SYSOUT;
//*
//*-------------------------------------------------------------
//* LINK-EDIT STEP:
//*-------------------------------------------------------------
//LKED    EXEC PGM=IEWL,PARM='&LPARM;',COND=(4,LT)
//SYSLIB    DD DSN=&VSCCHD;&CVER;&CBASE;,DISP=SHR;
//          DD DSN=C370.LL.V2R1M0.COMMON.SIBMLINK,DISP=SHR
//          DD DSN=&COMHD;&COMVER;&COMBASE;,DISP=SHR;
//          DD DSN=C370.V2R1M0.SEDCSPC,DISP=SHR
//          DD DSN=B37.SEZACMTX,DISP=SHR
//NEWOBJ    DD DSN=*.PRELNK.SYSMOD,DISP=(OLD,DELETE)
//OBJLIB    DD DSN=&OBJLIB;,DISP=SHR;
//SYSLMOD   DD DSN=&XWDLOAD;,DISP=SHR;
//SYSPRINT  DD SYSOUT=&SYSOUT;
//SYSUT1    DD DSN=&&SYSUT1;,UNIT=&WORKDA;,DISP=&LKDISP;,SPACE=&WRKSPC;
//*

Note: For more information about installing a reentrant module in the LPA area, see z/OS XL C/C++ User's Guide.

The following steps describe how to run your program:

Specify the IP address of the X server on which you want to display the application output by creating or modifying the user_id.XWINDOWS.DISPLAY data set. The following is an example of a line in this data set:
CHARM.RALEIGH.IBM.COM:0.0 or 9.67.43.79:0.0
Allow the host application access to the X server.
On the workstation where you want to display the application output, you must grant permission for the MVS host to access the X server. To do this, enter the xhost command:

xhost ralmvs1
If you have installed your program in the LPA as a reentrant module and you want to run it under TSO, enter the following:
PROGRAM1

Note: For more information about compiling and linking, see z/OS XL C/C++ User's Guide.