What is the meaning of Bus error 10 in C

Question

Below is my code    include  lt stdio h gt   include  lt string h gt   int main int argc  const char  argv          char  str    First string       char  str2    Second string        strcpy str  str2       return 0      It compiles just fine without any warning or errors  but when I run the code I get the error below  Bus error  10   What did I miss

User · Answer

Your code attempts to overwrite a string literal. This is undefined behaviour.

There are several ways to fix this:

use malloc() then strcpy() then free();
turn str into an array and use strcpy();
use strdup().

User · Answer

Let me explain why you do you got this error  quot Bus error  10 quot  char  str1    quot First string quot      for this statement the memory will be allocated into the CODE TEXT segment which is READ-ONLY  char  str2    quot Second string quot      for this statement the memory will be allocated into the CODE TEXT segment which is READ-ONLY  strcpy str1  str2      This function will copy the content from str2 into str1  this is not possible because you are try to perform READ WRITE operation inside the READ-ONLY segment Which was the root cause   If you want to perform string manipulation use automatic variables STACK segment  or dynamic variables HEAP segment  Vasanth

User · Answer

str2 is pointing to a statically allocated constant character array  You can t write to it over it  You need to dynamically allocate space via the  alloc family of functions

User · Answer

There is no space allocated for the strings  use array  or  pointers with malloc   and free    Other than that    import  lt stdio h gt   import  lt string h gt    should be    include  lt stdio h gt   include  lt string h gt    NOTE     anything that is malloc  ed must be free   ed you need to allocate n   1 bytes for a string which is of length n  the last byte is for  0    Please you the following code as a reference    include  lt stdio h gt   include  lt stdlib h gt   include  lt string h gt   int main int argc  char  argv            char  str1    First string       char  str1    First string is a big string       char  str2   NULL       if   str2    char    malloc sizeof char    strlen str1    1      NULL            printf  unable to allocate memory  n            return -1                 strcpy str2  str1        printf  str1    s  n   str1       printf  str2    s  n   str2        free str2       return 0

User · Answer

For one  you can t modify string literals  It s undefined behavior   To fix that you can make str a local array   char str      First string     Now  you will have a second problem  is that str isn t large enough to hold str2  So you will need to increase the length of it  Otherwise  you will overrun str - which is also undefined behavior   To get around this second problem  you either need to make str at least as long as str2  Or allocate it dynamically   char  str2    Second string   char  str   malloc strlen str2    1        Allocate memory     Maybe check for NULL   strcpy str  str2        Always remember to free it  free str     There are other more elegant ways to do this involving VLAs  in C99  and stack allocation  but I won t go into those as their use is somewhat questionable     As  SangeethSaravanaraj pointed out in the comments  everyone missed the  import  It should be  include    include  lt stdio h gt   include  lt string h gt

User · Answer

Whenever you are using pointer variables   the asterix   such as    char  str    First string     you need to asign memory to it   str   malloc strlen  str

User · Answer

string literals are non-modifiable in C

User · Answer

this is because str is pointing to a string literal means a constant string    but you are trying to modify it by copying    Note   if it would have been an error due to memory allocation  it would have been given segmentation fault at the run time  But this error  is coming due to constant string modification or you can go through the below for more details abt bus error       Bus errors are rare nowadays on x86 and occur when your processor cannot even attempt the memory access requested  typically     using a processor instruction with an address that does not satisfy its alignment requirements       Segmentation faults occur when accessing memory which does not belong to your process  they are very common and are typically the result of     using a pointer to something that was deallocated  using an uninitialized hence bogus pointer  using a null pointer  overflowing a buffer    To be more precise this is not manipulating the pointer itself that will cause issues  it s accessing the memory it points to  dereferencing

[c] What is the meaning of Bus: error 10 in C

Examples related to c