Hello,
[ No Cygwin-specific issues here. ]
The compiler and / or linker are allowed to place those string literals in
read-only storage, and apparently gcc under Cygwin does just that.
If you modify your program like this:
-==-
#include <string.h>
char *strsave(char *);
int main() {
// char *a = "I am a teacher";
// char *b = "You are a student";
char *a = strsave("I am a teacher");
char *b = strsave("You are a student");
printf("string_a = %s\nstring_b = %s\n", a, b);
copy_string(a, b);
printf("string_a = %s\nstring_b = %s\n", a, b);
}
int
copy_string(char *from, char *to) {
while((*to++ = *from++) != '\0');
}
char *
strsave(char *str)
{
char *newStr = (char *) malloc(strlen(str) + 1);
strcpy(newStr, str);
return newStr;
}
-==-
It will run without faulting and do what (I believe) you expect. Note you
are relying on the fact that "I am a teacher" is shorter than "You are a
student"
Randall Schulz
Mountain View, CA USA
At 19:09 2002-03-06, [EMAIL PROTECTED] wrote:
>Hi, gentleman, could you do me a favour?
>I had some trouble in running a C program.
>
>[C source code is]
>----- from here ----
>#include <stdio.h>
>
>int main() {
> char *a = "I am a teacher";
> char *b = "You are a student";
> printf("string_a = %s\nstring_b = %s\n", a, b);
> copy_string(a, b);
> printf("string_a = %s\nstring_b = %s\n", a, b);
>}
>
>int copy_string(char *from, char *to) {
> while((*to++ = *from++) != '\0');
>}
>----- end here ----
>
>[Compilation Tool]
> gcc version 2.95.3-5(cygwin)
>
>[Question]
> The compilation is passed, but after running the a.exe, the
>following message appeared and I got a a.exe.stackdump too.
>------
>string_a = I am a teacher
>string_b = You are a student
> 0 [main] a 1536 open stackdumpfile:Dumping stack trace to a.exe
>stackdump
>Segmentation fault (core dumped)
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