From: juhkivij AT utu DOT fi (Juha Kivijärvi)
Newsgroups: comp.os.msdos.djgpp
Subject: Problem with long parameters to system()
Date: 19 Oct 1998 12:34:50 GMT
Organization: University of Turku, Finland
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

I use DJGPP 2.0 / GCC 2.7.2 to compile these two short programs:


/* ------- a.c ------------------------ */

#include <stdio.h>

void main(int argc, char* argv[])
{
printf("%s\n", argv[1]);
}

/* ------- b.c ------------------------ */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

void main()
{
printf("system:\n");
system("a 123456789A123456789B123456789C123456789D123456789E123456789F123456789G123456789H123456789I123456789J123456789K123456789L123456789M123456789N123456789O");
printf("execl:\n");
execl("a", "", "123456789A123456789B123456789C123456789D123456789E123456789F123456789G123456789H123456789I123456789J123456789K123456789L123456789M123456789N123456789O"); 
}

/* ------------------------------------ */

Now, when I run b.exe, I get the following output:

system:
123456789A123456789B123456789C123456789D123456789E123456789F123456789G123456789H123456789I123456789J123456789K123456789L12345
execl:
Exiting due to signal SIGSEGV
Page fault at eip=0000676a, error=0004
eax=00008e00 ebx=000000b0 ecx=ffffffff edx=00052f1c esi=00000004 edi=00000001
ebp=00053018 esp=00052f1c cs=00a7 ds=00af es=00af fs=008f gs=00bf ss=00af
Call frame traceback EIPs:
  0x0000676a
  0x00006ebd
  0x00002977
  0x000016c3
  0x00001bfb


This raises two questions:

1) Why does system() call seem to truncate the command line to 128
   characters although the info page states that this shouldn't happen
   when calling other DJGPP compiled programs? What to do?
2) What am I doing wrong with execl()? This doesn't seem to have
   anything to do with the length of the parameter. Furthermore,
   replacing "" by "a" doesn't help.

Thanks for your time.
						          "
						Juha Kivijarvi
						juhkivij AT utu DOT fi