The concatenation expression is used for nonnumeric literals.
The concatenation expression is useful for adding control characters because it allows nonnumeric literals, symbolic constants and hexadecimal literals to be connected.
Use caution as Windows functions are invoked in this sample and USER32.LIB stored in the COBOL installation folder (directory) must be included at linkage.
This sample applies to Win32. However, similar processing will be required for linking to C with an operating system other than Win32.
000010 @OPTIONS MAIN,ALPHAL(WORD) 000020*---------------------------------------------------------------------- 000030* The concatenation expression can be used to connect nonnumeric 000035* literals. 000040*---------------------------------------------------------------------- 000050 IDENTIFICATION DIVISION. 000060 PROGRAM-ID. SAMPLE. 000070 DATA DIVISION. 000080 WORKING-STORAGE SECTION. 000090 01 TITLE-TXT PIC X(20). 000100 01 MSG-TXT PIC X(20). 000110 01 RET PIC S9(9) COMP-5 VALUE 0. 000120 PROCEDURE DIVISION. 000130*---------------------------------------------------------------------- 000140* Nonnumeric literals can be connected using &. 000150* As shown in the following example, this expression is useful for 000155* setting null terminating characters when linking to C. 000160* -> When passing character string data to C, a null character is 000170* required at the end of the character string. 000180* While reference modification could be used to accomplish the same 000185* result, the concatenation expression makes for easy and elegant 000187* coding. 000190*---------------------------------------------------------------------- 000200 MOVE "SAMPLE" & X"00" TO TITLE-TXT. 000210 MOVE "Hello COBOL!!" & X"00" TO MSG-TXT. 000220*---------------------------------------------------------------------- 000230 CALL "MessageBoxA" WITH STDCALL USING BY VALUE 0 000240 BY REFERENCE MSG-TXT 000250 BY REFERENCE TITLE-TXT 000260 BY VALUE 1 000270 RETURNING RET. 000280 EXIT PROGRAM. 000290 END PROGRAM SAMPLE.
