I am retrieving the environment variables in win32 using GetEnvironmentStrings()
. It returns a char*
.
I want to search this string(char pointer) for a specific environmental variable (yes I know I can use GetEnvironmentVariable()
but I am doing it this way because I also want to print all the environment variables on the console aswell - I am just fiddling around).
So I thought I would convert the char*
to an std::string & use find on it (I know I can also use a c_string find function but I am more concerned about trying to copy a char*
into a std::string
). But the following code seems to not copy all of the char*
into the std::string
(it makes me think there is a \0
character in the char*
but its not actually the end).
char* a = GetEnvironmentStrings();
string b = string(a, sizeof(a));
printf( "%s", b.c_str() ); // prints =::=
Is there a way to copy a char*
into a std::string
(I know I can use strcpy()
to copy a const char*
into a string but not a char*
).
You do not want to use sizeof()
in this context- you can just pass the value into the constructor. char*
trivially becomes const char*
and you don't want to use strcpy
or printf
either.
That's for conventional C-strings- however GetEnvironmentStrings()
returns a bit of a strange format and you will probably need to insert it manually.
const char* a = GetEnvironmentStrings();
int prev = 0;
std::vector<std::string> env_strings;
for(int i = 0; ; i++) {
if (a[i] == '\0') {
env_strings.push_back(std::string(a + prev, a + i));
prev = i;
if (a[i + 1] == '\0') {
break;
}
}
}
for(int i = 0; i < env_strings.size(); i++) {
std::cout << env_strings[i] << "\n";
}