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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><!-- DOS Environment --><HTML><HEAD><TITLE>DOS Environment</TITLE></HEAD><BODY BACKGROUND="spiral.gif" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#990099" ALINK="#FF0000"><TABLE WIDTH="98%"><TR><TD WIDTH=60 VALIGN=BOTTOM NOWRAP><IMG SRC="transp.gif" ALT="" WIDTH=60 HEIGHT=20></TD><TD><!-- Ab hier Seitentext: --><BIG><BR><P><STRONG><U>II.1.4 DOS Environment</U></STRONG></P><P>To specify a search path for include files, an optional environment variableASEM51INC can be defined:</P><P><BLOCKQUOTE><STRONG><PRE> SET ASEM51INC=<path></PRE></STRONG></BLOCKQUOTE></P><P><path> may be any number of directories separated by ';' characters.Be sure that the whole definition doesn't contain any blanks or tabs!If ASEM51INC is defined, the assembler searches the specified <path> forinclude files that can neither be found in the working directory, nor inthe search path specified with the /INCLUDES option.The <path> directories will be searched from left to right.</P><P><BR><STRONG>Examples:</STRONG><BLOCKQUOTE><STRONG><PRE>1.) SET ASEM51INC=C:\ASEM51\MCU;D:\MICROS\MCS51\INCL</PRE></STRONG><BLOCKQUOTE>If include files can neither be found in the working directory,nor in the /INCLUDES path (if specified), the assembler searchesnext C:\ASEM51\MCU and finally D:\MICROS\MCS51\INCL.</BLOCKQUOTE><STRONG><PRE>2.) SET ASEM51INC=C:\ASEM51\MCU;%PATH%</PRE></STRONG><BLOCKQUOTE>If ASEM51INC is defined as above in AUTOEXEC.BAT after the PATHstatement, the assembler finally searches the directory C:\ASEM51\MCUand then all the directories, contained in the DOS program searchpath, from left to right!</BLOCKQUOTE></BLOCKQUOTE></P><P>The maximum length of <path> is limited to 255 characters. This cannot beexceeded with the SET command of the DOS command interpreter COMMAND.COM,but with third party command interpreters like 4DOS (max. 512 characters)!</P><P>Note that trailing blanks and tabs behind the names of environment variablesseem to be considered significant under <NOBR>MS-DOS</NOBR>!If one subsequently defines<STRONG><PRE> SET ASEM51INC =C:\ASEM51\MCUand SET ASEM51INC=C:\8051\MCU</PRE></STRONG>there will be two (!) entries concurrently in the DOS environment! However,the assembler will recognize the second one only. Since DOS doesn't truncatetrailing blanks and tabs from variable names, the assembler can't do thiseither! That is why you should be sure, to always define the environmentvariable without blanks and tabs.</P></BIG><!-- Seitentext Ende --><P><BR><BR><CENTER><TABLE WIDTH="70%"><TR><TH><A HREF="contents.htm"><IMG SRC="home.gif" ALT="[contents]" BORDER=0 WIDTH=32 HEIGHT=32></A></TH> <TH><A HREF="doswin.htm"><IMG SRC="up.gif" ALT="[up]" BORDER=0 WIDTH=32 HEIGHT=32></A></TH> <TH><A HREF="doscmd.htm"><IMG SRC="back.gif" ALT="[back]" BORDER=0 WIDTH=32 HEIGHT=32></A></TH> <TH><A HREF="borland.htm"><IMG SRC="next.gif" ALT="[next]" BORDER=0 WIDTH=32 HEIGHT=32></A></TH></TR></TABLE></CENTER></P></TD></TR></TABLE></BODY></HTML>⌨️ 快捷键说明
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