Segmentation fault when I pass a char pointer to a function in C. Post: 303016290

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Top Forums Programming Segmentation fault when I pass a char pointer to a function in C. Post 303016290 by dryden on Tuesday 24th of April 2018 02:25:18 AM

04-24-2018

Registered User

Quote:

Originally Posted by Corona688

It's implicitly a pointer, implemented as one internally, but the same way you're not allowed to change a string's contents, you're not allowed to change its value. Hardcoded.

Those... aren't really similar things. The array's address (the name) is only known at compile time, or debug info, but in the compiled code the 'name' is effaced and you're simply dealing with addresses hardcoded into the code.

Thus, there isn't really anything you can modify unless you were to write the code segment.

The string, I guess it could also be located in a code segment, but more likely is that they are actual data values in a read-only data segment.

As such, the array is not really a pointer, there is no variable anywhere holding its address. So, it's no different from not being able to change the address of some int value that you have defined.

When you do

Code:

char arr[20]; char *p = arr;

That's technically no different from

Code:

int i; int *q = &i;

But I find the biggest annoyance(?) of arrays and structs to be that you can only initialize them at declaration?

dryden

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gzexe

GZEXE(1)						      General Commands Manual							  GZEXE(1)

NAME

       gzexe - compress executable files in place

SYNOPSIS

       gzexe name ...

DESCRIPTION

       The  gzexe  utility  allows you to compress executables in place and have them automatically uncompress and execute when you run them (at a
       penalty in performance).  For example if you execute ``gzexe /usr/bin/gdb'' it will create the following two files:
	   -rwxr-xr-x  1 root root 1026675 Jun	7 13:53 /usr/bin/gdb
	   -rwxr-xr-x  1 root root 2304524 May 30 13:02 /usr/bin/gdb~
       /usr/bin/gdb~ is the original file and /usr/bin/gdb is the self-uncompressing executable file.  You can remove /usr/bin/gdb~ once  you  are
       sure that /usr/bin/gdb works properly.

       This utility is most useful on systems with very small disks.

OPTIONS

       -d     Decompress the given executables instead of compressing them.

SEE ALSO

       gzip(1), znew(1), zmore(1), zcmp(1), zforce(1)

CAVEATS

       The  compressed executable is a shell script.  This may create some security holes.  In particular, the compressed executable relies on the
       PATH environment variable to find gzip and some standard utilities (basename, chmod, ln, mkdir, mktemp, rm, sleep, and tail).

BUGS

       gzexe attempts to retain the original file attributes on the compressed executable, but you may have to fix them manually  in  some  cases,
       using chmod or chown.

																	  GZEXE(1)

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