Are string literals const?

c string constants literals
peoro picture peoro · Dec 20, 2010 · Viewed 8.7k times · Source

Both GCC and Clang do not complain if I assign a string literal to a char*, even when using lots of pedantic options (-Wall -W -pedantic -std=c99):

char *foo = "bar";

while they (of course) do complain if I assign a const char* to a char*.

Does this mean that string literals are considered to be of char* type? Shouldn't they be const char*? It's not defined behavior if they get modified!

And (an uncorrelated question) what about command line parameters (ie: argv): is it considered to be an array of string literals?

Answer

Johannes Schaub - litb picture Johannes Schaub - litb · Dec 20, 2010

They are of type char[N] where N is the number of characters including the terminating \0. So yes you can assign them to char*, but you still cannot write to them (the effect will be undefined).

Wrt argv: It points to an array of pointers to strings. Those strings are explicitly modifiable. You can change them and they are required to hold the last stored value.

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