char *test = (char*) malloc(12*sizeof(char));
+-+-+-+-+-+-+-+-+-+-+-+-+
test--->|x|x|x|x|x|x|x|x|x|x|x|x| (uninitialized memory, heap)
+-+-+-+-+-+-+-+-+-+-+-+-+
test = "testingonly";
+-+-+-+-+-+-+-+-+-+-+-+-+
test + |x|x|x|x|x|x|x|x|x|x|x|x|
| +-+-+-+-+-+-+-+-+-+-+-+-+
| +-+-+-+-+-+-+-+-+-+-+-+-+
+->|t|e|s|t|i|n|g|o|n|l|y|0|
+-+-+-+-+-+-+-+-+-+-+-+-+
free(test); // error, because test is no longer pointing to allocated space.
Instead of changing the pointer test
, you need to copy the string "testingonly"
into the allocated place using e.g. strcpy
or use strdup
. Note that functions like malloc
and strdup
return NULL
if insufficient memory is available, and thus should be checked.
char *test = (char*) malloc(12*sizeof(char));
strcpy(test, "testingonly");
+-+-+-+-+-+-+-+-+-+-+-+-+
test--->|t|e|s|t|i|n|g|o|n|l|y|0|
+-+-+-+-+-+-+-+-+-+-+-+-+
or
char *test = strdup("testingonly");
+-+-+-+-+-+-+-+-+-+-+-+-+
test--->|t|e|s|t|i|n|g|o|n|l|y|0|
+-+-+-+-+-+-+-+-+-+-+-+-+