PL/I preprocessor: Difference between revisions

Revision as of 00:18, 7 December 2017

Revision as of 00:56, 24 October 2018

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==Example==

The following example for IBM PL/I for OS/2 illustrates the use of a preprocessor procedure to implement a C-like write statement for PL/I.<ref>{{cite web|last=Sturm|first=Eberhard|title=UIO-Makros für Builtin-Funktionen fileread und filewrite|url=http://www.uni-muenster.de/ZIV.EberhardSturm/uio.cpy|accessdate=January 22, 2012}}</ref> The procedure would be called by coding the statement {{code|uwrite file(filename) from(varying_string) count(byte_count);}} {{mono|<var>Byte_count</var>}} is optional and defaults to the length of {{mono|<var>varying_string</var></code> if omitted.

<source lang="rexx" line highlight="1,25,26">

<pre>

%uwrite:

procedure keys (File, From, Count);

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%end;

%act uwrite;

</presource>

The statement {{code|uwrite file(file_name) from(var_str) count(64);}} generates the following:

<source lang="rexx">

<pre>

do;

dcl Count00001 fixed bin (15);

Count00001 = filewrite(file_name, ptradd(addr(var_str), 2), min(length(var_str), 64));

end;

</presource>

==Evolution==