The program LONGPATH may be used to add aditional directories to an existing
path and thus produce a path longer than the DOS limit of about 125
characters. It may also be used to delete or replace an existing path.


Call: C>LONGPATH [additional path info] ( to add to existing path )
C>LONGPATH path=[new path] ( to replace existing path )
C>LONGPATH path= ( to delete existing path )


Return code: 0 successful (path added or deleted)
1 no parms or more than 1 parm on command line (path not changed)
2 not enough environment space (path not changed)


Sample use:

C>path
PATH=D:\;C:\

C>longpath ;c:\dos;c:\util

LONGPATH successful. New PATH is:
PATH=D:\;C:\;c:\dos;c:\util

C>longpath path=

LONGPATH successful. PATH deleted.

C>longpath path=d:\;c:\

LONGPATH successful. New PATH is:
PATH=d:\;c:\

C>_


Notes: The number of characters that can be added to the path at one time is
limited by the length of the command line. Therefore, for a really
really long path it is necessary to run the LONGPATH program several
times.

The use of %PATH% to access the path environment variable from within
a batch file will not work if the path is longer than about 125
characters.

To delete a path longer than 125 characters use the 'longpath path='
option. The results of using the DOS 'set path=' command is
unpredictable.

To increase the size of the environment include the SHELL command
in your config.sys file.


For the technically inclined:

The following is the source code for the LONGPATH program

/* Program to append additional information to the PATH environment variable */
/* */
/* This program may be used to add additional sub directories to the path */
/* and thus produce a path longer than the DOS limit of about 125 characters */
/* */
/* Call: C>LONGPATH [additional path info] ( to add to existing path ) */
/* C>LONGPATH path=[new path] ( to replace existing path ) */
/* C>LONGPATH path= ( to delete existing path ) */
/* */
/* Return code = 0 successful - path added or deleted */
/* 1 no parms or more than 1 parm on command line */
/* 2 not enough environment space */
/* */
/* Note: This program was compiled with Borland's Turbo C compiler */
/* version 2.0 using the small memory model */

#include
#include
#include
#include

typedef enum {false, true} boolean;
typedef unsigned char byte;
typedef unsigned int word;

typedef struct /* Program Segment Prefix - PSP */
{
char pspfiller1[22]; /* filler */
word pspprior; /* segment of parent */
char pspfiller2[20]; /* more filler */
word pspenv; /* segment of environment */
} psphdr;

boolean startup(char *argp[], char **npath, char far **envpp)
{ /* setup new path and pointer */
boolean serror; /* to environment */
int i,j,k;
psphdr far *pspp; /* pointer to PSP */
word far *envsp; /* pointer to size of environment */
char *pathp; /* current PATH */

serror=false;
pathp=getenv("PATH");
k=strlen(pathp);
if (strnicmp(argp[1],"PATH=",5)==0) /* get memory for new path */
{ /* and construct new path */
i=strlen(argp[1])+1;
*npath=malloc(i);
strcpy(*npath,argp[1]);
for (j=0; j<4; j++)
(*npath)[j]=(*npath)[j] & 0xdf;
}
else
{
i=k+strlen(argp[1])+strlen("PATH=")+1;
*npath=malloc(i);
strcpy(*npath,"PATH=");
if (pathp!=NULL)
strcat(*npath,pathp);
strcat(*npath,argp[1]);
}
putenv(*npath);

pspp=MK_FP(_psp,0x0000); /* follow psp chain to top and get */
while (pspp!=MK_FP(pspp->pspprior,0x0000)) /* pointer to environment */
pspp=MK_FP(pspp->pspprior,0x0000); /* and to size of environ */
*envpp=(char far *)MK_FP(pspp->pspenv,0x0000);
envsp=MK_FP(pspp->pspenv-1,0x0003);
j=1;
for (i=0; environ[i]!=NULL; i++) /* compute total size of all */
{ /* environment variables and */
if (strcmp(environ[i],"PATH=")!=0) /* set error if not enough room */
j=j+strlen(environ[i])+1;
}
i=*envsp<<4;
if (j>i)
serror=true;
return(serror);
}

void main(int ict, char *argp[])
{
boolean delpath;
int retcode;
word i,j,k;
char *npath; /* pointer to new path */
char far *envpp; /* pointer to environment */

delpath=false;
if (ict!=2) /* check for proper number of args */
{
puts("\nPath to be added to current path must be entered on command line.");
puts(" i.e. C>LONGPATH ;C:\\ADDED\\PATH");
retcode=1;
}
else
{
if (startup(argp,&npath,&envpp)==true) /* get new path and env ptr */
{
puts("\nNot enough environment space. PATH not changed.");
retcode=2;
}
else
{
j=0;
for (i=0; environ[i]!=NULL; i++) /* rebuild entire environment */
{
if (strcmp(environ[i],"PATH=")!=0)
{
k=strlen(environ[i])+1;
movedata(_DS,(unsigned)environ[i],FP_SEG(envpp),FP_OFF(envpp),k);
j=j+k;
envpp=MK_FP(FP_SEG(envpp),j);
}
else
{
delpath=true;
}
}
*(char far *)envpp='\0'; /* set end of environment */
retcode=0;
}
}
if (retcode==0)
{
if (delpath==false)
{
puts("\nLONGPATH successful. New PATH is:");
printf("%s\n",npath);
}
else
{
puts("\nLONGPATH successful. PATH deleted.");
}
}
exit(retcode);
}